@misc{Dataset,
 author={C S Knox and A Yagmur and J J Burton and Z Aslam and P M Shepley and J Harrington and E H Linfield and J R Freeman and S Sasaki},
 title={Dataset associated with {Optimisation of the growth of Sb$_2$Te$_3$ by MBE using thermally cracked Sb}},
 doi={10.5518/1654},
 howpublished={\url{https://doi.org/10.5518/1654}},
}
@book{Adachi1994,
   author = {Sadao Adachi},
   keywords = {Gallium arsenide semiconductors.
Semiconductors Surface properties.
Layer structure (Solids)
Superlattices as materials.
Energy-band theory of solids.},
   pages = {xix, 675 p},
   publisher = {World Scientific},
   title = {GaAs and related materials : bulk semiconducting and superlattice properties},
   year = {1994}
}
@article{Acun2015,
   abstract = {Recently, several research groups have reported the growth of germanene, a new member of the graphene family. Germanene is in many aspects very similar to graphene, but in contrast to the planar graphene lattice, the germanene honeycomb lattice is buckled and composed of two vertically displaced sub-lattices. Density functional theory calculations have revealed that free-standing germanene is a 2D Dirac fermion system, i.e. the electrons behave as massless relativistic particles that are described by the Dirac equation, which is the relativistic variant of the Schrodinger equation. Germanene is a very appealing 2D material. The spin-orbit gap in germanene (similar to 24 meV) is much larger than in graphene (<0.05 meV), which makes germanene the ideal candidate to exhibit the quantum spin Hall effect at experimentally accessible temperatures. Additionally, the germanene lattice offers the possibility to open a band gap via for instance an externally applied electrical field, adsorption of foreign atoms or coupling with a substrate. This opening of the band gap paves the way to the realization of germanene based field-effect devices. In this topical review we will (1) address the various methods to synthesize germanene (2) provide a brief overview of the key results that have been obtained by density functional theory calculations and (3) discuss the potential of germanene for future applications as well for fundamentally oriented studies.},
   author = {A Acun and L Zhang and P Bampoulis and M Farmanbar and A van Houselt and A N Rudenko and M Lingenfelder and G Brocks and B Poelsema and M I Katsnelson and H J W Zandvliet},
   issue = {44},
   journal = {J Phys-Condens Mat},
   keywords = {germanene
2d materials
scanning tunneling microscopy
topological phase-transition
field-effect transistors
augmented-wave method
hgte quantum-wells
tunable band-gap
surface-adsorption
boron-nitride
silicene
crystalline
1st-principles},
   title = {Germanene: the germanium analogue of graphene},
   volume = {27},
   year = {2015}
}
@article{Adroguer2010,
   abstract = {We consider the proximity effect between a singlet s-wave superconductor and the edge of a quantum spin Hall (QSH) topological insulator. We establish that Andreev reflection at a QSH edge state/superconductor interface is perfect while nonlocal Andreev processes through the superconductor are totally suppressed. We compute the corresponding conductance and noise.},
   author = {P Adroguer and C Grenier and D Carpentier and J Cayssol and P Degiovanni and E Orignac},
   issue = {8},
   journal = {Phys Rev B},
   keywords = {hgte quantum-wells
transition
transport},
   pages = {81303},
   title = {Probing the helical edge states of a topological insulator by Cooper-pair injection},
   volume = {82},
   year = {2010}
}
@book{etal1997,
   author = {J Thornton et al},
   pages = {64},
   title = {Scanning Probe Microscopy Training Notebook},
   year = {1997}
}
@misc{,
   author = {R R Alfano and United States. National Aeronautics and Space Administration.},
   keywords = {Absorption spectra.
Energy gap (Solid state).
Gallium arsenides.
Indium phosphides.
Photoluminescene.
Quantum wells.
Semiconductors (Materials).
Solar cells.},
   title = {Investigation of the basic physics of high efficiency semiconductor hot carrier solar cell annual status report for NASA grant #NAG 3-1490}
}
@article{Alicea2011,
   abstract = {The synthesis of a quantum computer remains an ongoing challenge in modern physics. Whereas decoherence stymies most approaches, topological quantum computation schemes evade decoherence at the hardware level by storing quantum information non-locally. Here we establish that a key operation-braiding of non-Abelian anyons-can be implemented using one-dimensional semiconducting wires. Such wires can be driven into a topological phase supporting long-sought particles known as Majorana fermions that can encode topological qubits. We show that in wire networks, Majorana fermions can be meaningfully braided by simply adjusting gate voltages, and that they exhibit non-Abelian statistics like vortices in a p + ip superconductor. We propose experimental set-ups that enable probing of the Majorana fusion rules and the efficient exchange of arbitrary numbers of Majorana fermions. This work should open a new direction in topological quantum computation that benefits from physical transparency and experimental feasibility.},
   author = {J Alicea and Y Oreg and G Refael and F von Oppen and M P A Fisher},
   issue = {5},
   journal = {Nat Phys},
   keywords = {computation
anyons},
   pages = {412-417},
   title = {Non-Abelian statistics and topological quantum information processing in 1D wire networks},
   volume = {7},
   year = {2011}
}
@article{Altarelli1983,
   author = {M Altarelli},
   issue = {2},
   journal = {Phys Rev B},
   pages = {842-845},
   title = {Electronic-Structure and Semiconductor-Semimetal Transition in InAs-GaSb Super-Lattices},
   volume = {28},
   year = {1983}
}
@article{Altarelli1987,
   author = {M Altarelli and J C Maan and L L Chang and L Esaki},
   issue = {18},
   journal = {Phys Rev B},
   pages = {9867-9870},
   title = {Electronic States and Quantum Hall-Effect in GaSb-InAs-GaSb Quantum-Wells},
   volume = {35},
   year = {1987}
}
@article{Alzamil2011,
   abstract = {Electron mobility calculations of n-type InAs were carried out at temperatures from 10 K up to 400 K and doping concentration from 6x10(20) m(-3) to 2.5x10(21) m(-3). The numerical computations were performed using relaxation time approximation taking into account some elastic scattering mechanisms. The temperature dependence of the electron drift mobility showed a noticeable decrease in the mobility with decreasing of temperature. It was changed, nearly, from the value 40000 cm(2)/V.s at room temperature to nearly 1300 cm(2)/V.s at 10 K. The decrease of the calculated drift mobility could be attributed to the influence of the ionized impurity scattering at low temperatures.},
   author = {M A Alzamil},
   issue = {2},
   journal = {Dig J Nanomater Bios},
   keywords = {band gap
mobility
acoustic phonon scattering
impurity scattering},
   pages = {725-729},
   title = {Electron Mobility Calculations of N-InAs},
   volume = {6},
   year = {2011}
}
@article{Armarego2000,
   abstract = {In this paper predictive models for the force components, chip flow and power in single and multi pass turning of helical vee grooves as well as single pass turning at high and low feed to depth of cut ratios with triangular profiled form tools have been developed. The predictive models are based on generalised mechanics of cutting analyses for machining with single and multi-edge form tools together with a 'generic' database of basic cutting quantities and edge force coefficients found from 'classical' orthogonal cutting tests. The mathematical models allow for all the tool and cut geometrical variables as well as the cutting speed while the database allows for the tool-workpiece material effects and tool coatings. The models have been experimentally verified over a wide range of operation variables and their predictive capabilities estimated in terms of the percentage deviations between the measured and predicted forces. The developed models are capable of predicting the tangential, feed and radial forces within a deviation of 10 % 'on average'. This investigation has enabled the 'Unified Mechanics of Cutting Approach' to performance prediction to be extended to include machining with form tools.},
   author = {E J A Armarego and A B Herath},
   journal = {Cirp Annals 2000: Manufacturing Technology},
   keywords = {cutting
form tool operations
predictive force modelling},
   pages = {25-30},
   title = {Predictive models for machining with multi-edge form tools based on a generalised cutting approach},
   year = {2000}
}
@article{Attiga1996,
   abstract = {The ultrastructure of euspermiogenesis and euspermatozoa of Clypeomorus bifasciata and C. tuberculatus are almost identical. Early spermatids have oval to spherical nuclei, sparse endoplasmic reticulum, few mitochondria, and a well-developed Golgi complex with many vesicles in its vicinity. Acrosome differentiation occurs anywhere within the cytoplasm, and begins with a proacrosomal vesicle, which becomes cup-shaped and plugged at its edges with a dense interstitial granule. Microtubules are embedded in the matrix between the outer and inner acrosomal membranes. The acrosomal vesicle becomes aligned parallel to the anteroposterior nuclear axis, and changes into an inverted flask shape, with two external supporting structures at its basal margins. The interstitial granule becomes hat-shaped, separating the acrosome from the nucleus. The mature acrosome consists of a flat cone with microtubules in its core, an acrosomal rod-like material, and a basal plate. Nuclear shape changes from spherical to hammer-head to club-shape, with a posterior invagination enclosing the initial axonemal portion. The fine chromatin material of early spermatids changes to fibrillar, lamellar, and finally very compact material. The euspermatozoan midpiece originates from fusion of spermatid mitochondria into four large spheres, which are later organized into four non-helical mitochondrial elements, two of which are large and the other two are extremely small. A dense ring structure marks the junction between the midpiece and the glycogen piece. The latter consists of nine tracts of glycogen granules surrounding nine axonemal doublets. The results of this study suggest that acrosomal ultrastructure could be used to establish phylogenetic relationships in Cerithiacea at the generic level.},
   author = {F A Attiga and H A AlHajj},
   issue = {1-2},
   journal = {Malacologia},
   keywords = {gulf-of-aqaba
sperm morphology
marine snail
systematic importance
spermatozoa
spermiogenesis
euspermatozoa
gastropoda
paraspermatozoa
mesogastropoda},
   pages = {47-58},
   title = {Ultrastructural study of euspermiogenesis in Clypeomorus bifasciata and Clypeomorus tuberculatus (Prosobranchia: Cerithiidae) with emphasis on acrosome formation},
   volume = {38},
   year = {1996}
}
@article{Averkiev1999,
   abstract = {Spin relaxation in-plane anisotropy is predicted for heterostructures based on zinc-blende semiconductors. It is shown that it manifests itself especially brightly if the two spin relaxation mechanisms (Dyakonov-Perel and Rashba) are comparable in efficiency. It is demonstrated that for the quantum well grown along the [001] direction, the main axes of spin relaxation rate tensor are [110] and [1 (1) over bar 0]. [S0163-1829(99)09643-5].},
   author = {N S Averkiev and L E Golub},
   issue = {23},
   journal = {Phys Rev B},
   keywords = {weak antilocalization
quantum-wells
magnetoresistance},
   pages = {15582-15584},
   title = {Giant spin relaxation anisotropy in zinc-blende heterostructures},
   volume = {60},
   year = {1999}
}
@misc{Batley2015,
   author = {Joseph Thomas Batley},
   institution = {University of Leeds (School of Physics and Astronomy)},
   title = {Spin transport in lateral spin valves},
   year = {2015}
}
@article{Bastard1982,
   author = {G Bastard},
   issue = {12},
   journal = {Phys Rev B},
   pages = {7584-7597},
   title = {Theoretical Investigations of Super-Lattice Band-Structure in the Envelope-Function Approximation},
   volume = {25},
   year = {1982}
}
@article{Beenakker2013,
   abstract = {The helical edge state of a quantum spin-Hall insulator can carry a supercurrent in equilibrium between two superconducting electrodes (separation L, coherence length xi). We calculate the maximum (critical) current I-c that can flow without dissipation along a single edge, going beyond the short-junction restriction L << xi of earlier work, and find a dependence on the fermion parity of the ground state when L becomes larger than xi. Fermion-parity conservation doubles the critical current in the low-temperature, long-junction limit, while for a short junction I-c is the same with or without parity constraints. This provides a phase-insensitive, dc signature of the 4 pi-periodic Josephson effect. DOI: 10.1103/PhysRevLett.110.017003},
   author = {C W J Beenakker and D I Pikulin and T Hyart and H Schomerus and J P Dahlhaus},
   issue = {1},
   journal = {Phys Rev Lett},
   keywords = {josephson-junctions
majorana fermions
nanowire
superconductor
signature},
   title = {Fermion-Parity Anomaly of the Critical Supercurrent in the Quantum Spin-Hall Effect},
   volume = {110},
   year = {2013}
}
@article{Benyahia2016,
   abstract = {High-quality InAs epilayers were grown onto GaAs (001) substrate by molecular beam epitaxy. The optimal growth conditions were examined over a wide range of substrate temperature, substrate offcut orientation, and As-4/In flux ratio. The surface morphology, electrical and structural properties were investigated by Nomarski optical microscopy, Hall effect measurement, and X-ray diffraction, respectively. It is worth noting that InAs layers grown on GaAs (001) substrate with 2 degrees offcut towards < 110 > have better crystalline quality and electrical properties than that grown on GaAs substrate without offcut. The results indicated that the layers grown at 400 degrees C, with a group V/III flux ratio of 8.5, yielded to the highest electrical quality, with a Hall mobility of 22,420 cm(2)/Vs at 80 K and 12,970 cm(2)/Vs at room temperature. It is found that the top part of 5 mu m-thick InAs layer exhibits a high Hall mobility of 77,380 and 25,275 cm(2)/Vs, at 80 and 300 K, respectively.},
   author = {D Benyahia and L Kubiszyn and K Michalczewski and A Keblowski and P Martyniuk and J Piotrowski and A Rogalski},
   issue = {9},
   journal = {Opt Quant Electron},
   keywords = {mbe
inas
gaas
hall effect
x-ray diffraction
transport-properties
epilayers
size
mbe},
   title = {Molecular beam epitaxial growth and characterization of InAs layers on GaAs (001) substrate},
   volume = {48},
   year = {2016}
}
@article{Bernevig2006,
   abstract = {We show that the quantum spin Hall (QSH) effect, a state of matter with topological properties distinct from those of conventional insulators, can be realized in mercury telluride-cadmium telluride semiconductor quantum wells. When the thickness of the quantum well is varied, the electronic state changes from a normal to an "inverted" type at a critical thickness d(c). We show that this transition is a topological quantum phase transition between a conventional insulating phase and a phase exhibiting the QSH effect with a single pair of helical edge states. We also discuss methods for experimental detection of the QSH effect.},
   author = {B A Bernevig and T L Hughes and S C Zhang},
   issue = {5806},
   journal = {Science},
   keywords = {semiconductors
lattice},
   pages = {1757-1761},
   title = {Quantum spin Hall effect and topological phase transition in HgTe quantum wells},
   volume = {314},
   year = {2006}
}
@article{Bernevig2005,
   abstract = {We present an analysis for two recent experiments in bulk strained semiconductors and show that a new, previously overlooked, strain spin-orbit coupling term may play a fundamental role. We propose simple experiments that could clarify the origin of strain-induced spin-orbit coupling terms in inversion asymmetric semiconductors. We predict that a uniform magnetization parallel to the electric field will be induced for specific directions of the applied electric field. We also propose special geometries to detect spin currents in strained semiconductors.},
   author = {B A Bernevig and S C Zhang},
   issue = {11},
   journal = {Phys Rev B},
   keywords = {conduction-band
electric-field
orientation},
   pages = {115204},
   title = {Spin splitting and spin current in strained bulk semiconductors},
   volume = {72},
   year = {2005}
}
@article{Beukman2017,
   abstract = {The spin-orbit interaction is investigated in a dual gated InAs/GaSb quantum well. Using an electric field, the quantum well can be tuned between a single-carrier regime with exclusively electrons as carriers and a two-carrier regime where electrons and holes coexist. The spin-orbit interaction in both regimes manifests itself as a beating in the Shubnikov-de Haas oscillations. In the single-carrier regime the linear Dresselhaus strength is characterized by beta = 28.5 meV angstrom and the Rashba coefficient a is tuned from 75 to 53 meV angstrom by changing the electric field. In the two-carrier regime a quenching of the spin splitting is observed and attributed to a crossing of spin bands.},
   author = {A J A Beukman and F K de Vries and J van Veen and R Skolasinski and M Wimmer and F M Qu and D T de Vries and B M Nguyen and W Yi and A A Kiselev and M Sokolich and M J Manfra and F Nichele and C M Marcus and L P Kouwenhoven},
   issue = {24},
   journal = {Phys Rev B},
   keywords = {electron-gas
heterostructures
inas
oscillations
spintronics
system
layers},
   pages = {241401},
   title = {Spin-orbit interaction in a dual gated InAs/GaSb quantum well},
   volume = {96},
   year = {2017}
}
@article{Bir1975,
   author = {G L Bir and A G Aronov and G E Pikus},
   issue = {4},
   journal = {Zh Eksp Teor Fiz+},
   pages = {1382-1397},
   title = {Spin Relaxation of Electrons Scattered by Holes},
   volume = {69},
   year = {1975}
}
@article{Bluyssen1979,
   author = {H Bluyssen and J C Maan and P Wyder and L L Chang and L Esaki},
   issue = {1},
   journal = {Solid State Commun},
   pages = {35-38},
   title = {Cyclotron-Resonance in an InAs-GaSb Super-Lattice},
   volume = {31},
   year = {1979}
}
@article{Bluyssen1982,
   author = {H J A Bluyssen and J C Maan and P Wyder and L L Chang and L Esaki},
   issue = {8},
   journal = {Phys Rev B},
   pages = {5364-5372},
   title = {Cyclotron-Resonance and Shubnikov-de Haas Experiments in a N-InAs-GaSb Super-Lattice},
   volume = {25},
   year = {1982}
}
@article{Bockrath1999,
   abstract = {Electron transport in conductors is usually well described by Fermi-liquid theory, which assumes that the energy states of the electrons near the Fermi level E(F) are not qualitatively altered by Coulomb interactions. In one-dimensional systems, however, even weak Coulomb interactions cause strong perturbations, The resulting system, known as a Luttinger liquid, is predicted to be distinctly different from its two- and three-dimensional counterparts(1). For example, tunnelling into a Luttinger liquid at energies near the Fermi level is predicted to be strongly suppressed, unlike in two- and three-dimensional metals. Experiments on one-dimensional semiconductor wires(2,3) have been interpreted by using Luttinger-liquid theory, but an unequivocal verification of the theoretical predictions has not yet been obtained, Similarly, the edge excitations seen in fractional quantum Hall conductors are consistent with Luttinger-liquid behaviour(4,5), but recent experiments failed to confirm the predicted relationship between the electrical properties of the bulk state and those of the edge states(6). Electrically conducting single-walled carbon nanotubes (SWNTs) represent quantum wires(7-10) that may exhibit Luttinger-liquid behaviour(11,12). Here we present measurements of the conductance of bundles ('ropes') of SWNTs as a function of temperature and voltage that agree with predictions for tunnelling into a Luttinger liquid. In particular, we find that the conductance and differential conductance scale as power laws with respect to temperature and bias voltage, respectively, and that the functional forms and the exponents are in good agreement with theoretical predictions.},
   author = {M Bockrath and D H Cobden and J Lu and A G Rinzler and R E Smalley and L Balents and P L McEuen},
   issue = {6720},
   journal = {Nature},
   keywords = {quantum wires
temperatures
conductance},
   pages = {598-601},
   title = {Luttinger-liquid behaviour in carbon nanotubes},
   volume = {397},
   year = {1999}
}
@article{Bradshaw2000,
   abstract = {We report our progress to date in the development of type-II interband cascade (IC) lasers emitting in the mid-IR (3.8-to-4.0 mu m) spectral region. We have demonstrated significant improvements over previously reported results in terms of differential external quantum efficiency (similar to 500%), peak power (>4 W/facet), peak power conversion efficiency (similar to 7%), maximum operating temperature (217 K), and confinuous-wave (cw) operation. We briefly review some results for pulsed excitation and then present more detailed operating characteristics for the cw performance of our lasers, including the output power characteristics and the dependence of the output spectrum on current.},
   author = {J L Bradshaw and R Q Yang and J D Bruno and J T Pham and D E Wortman},
   journal = {In-Plane Semiconductor Lasers Iv},
   keywords = {mid-infrared
mid-ir
interband
cascade lasers
type-ii quantum wells
inas/gainsb
cw
quantum-wells},
   pages = {129-135},
   title = {Mid-IR type-II InAs/GaInSb interband cascade lasers},
   volume = {3947},
   year = {2000}
}
@article{Breitsamter2008,
   abstract = {This paper presents selected results from extensive experimental investigations on turbulent flow fields and unsteady surface pressures caused by leading-edge vortices, in particular, for vortex breakdown flow. Such turbulent flows may cause severe dynamic aeroelastic problems like wing and/or fin buffeting on fighter-type aircraft. The wind tunnel models used include a generic delta wing as well as a detailed aircraft configuration of canard-delta wing type. The turbulent flow structures are analyzed by root-mean-square and spectral distributions of velocity and pressure fluctuations. Downstream of bursting local maxima of velocity fluctuations occur in a limited radial range around the vortex center. The corresponding spectra exhibit significant peaks indicating that turbulent kinetic energy is channeled into a narrow band. These quasi-periodic velocity oscillations arise from a helical mode instability of the breakdown flow. Due to vortex bursting there is a characteristic increase in surface pressure fluctuations with increasing angle of attack, especially when the burst location moves closer to the apex. The pressure fluctuations also show dominant frequencies corresponding to those of the velocity fluctuations. Using the measured flow field data, scaling parameters are derived for design purposes. It is shown that a frequency parameter based on the local semi-span and the sinus of angle of attack can be used to estimate the frequencies of dynamic loads evoked by vortex bursting. (C) 2007 Elsevier Ltd. All rights reserved.},
   author = {C Breitsamter},
   issue = {1},
   journal = {Prog Aerosp Sci},
   keywords = {fin
buffet
vortex
alleviation},
   pages = {48-65},
   title = {Unsteady flow phenomena associated with leading-edge vortices},
   volume = {44},
   year = {2008}
}
@article{Brown2005,
   abstract = {Superlattices composed of InAs and GaSb layers were first proposed for infrared detection in 1978. Later work by Smith and Mailhoit extended this premise to model InAs and InGaSb ternary layers for infrared detection in the long wavelength infrared range. What makes this material system so interesting is that these superlattice materials are essentially the III-V equivalent of HgCdTe materials. They have comparable absorption coefficients, the cut-off wavelengths can be continuously adjusted from short wavelength infrared to very long wavelength infrared (VLWIR), and photovoltaic operation is possible. One difference between these two materials is that with the superlattices the energy band structure, as well as the band gap, can be tailored to enhance detector performance. The band structure tailoring provides the superlattices with some advantages over HgCdTe alloys, particularly for very narrow band gaps. These superlattice advantages are a higher electron effective mass and large separation of the heavy and light-hole bands to suppress Auger recombination. These inherent properties of the InAs/GaInSb superlattices have made them an attractive material for VLWIR applications. As the type-II superlattice materials and devices mature, they will play a significant role as an alternative material for photovoltaic focal plane arrays in the LWIR and MWIR regimes as well. This paper provides an overview of the type-II superlattice development, accomplishments and issues.},
   author = {G J Brown},
   journal = {P Soc Photo-Opt Ins},
   keywords = {infrared
detector
superlattice
photodiodes
strained-layer superlattices
optical-properties
mu-m
photovoltaic detectors
inas/inxga1-xsb superlattices
gasb/inas superlattices
midinfrared detection
electronic-structure
interface structure
surface-morphology},
   pages = {65-77},
   title = {Type-II InAs/GaInSb superlattices for infrared detection: an overview},
   volume = {5783},
   year = {2005}
}
@article{Brown2015,
   abstract = {The objective of this work is to establish molecular beam epitaxy (MBE) growth processes that can produce high quality InAs/GaInSb superlattice (SL) materials specifically tailored for very long wavelength infrared (VLWIR) detection. To accomplish this goal, several series of MBE growth optimization studies, using a SL structure of 47.0 angstrom InAs/21.5 angstrom Ga0.75In0.25Sb, were performed to refine the MBE growth process and optimize growth parameters. Experimental results demonstrated that our "slow" MBE growth process can consistently produce an energy gap near 50 meV. This is an important factor in narrow band gap SLs. However, there are other growth factors that also impact the electrical and optical properties of the SL materials. The SL layers are particularly sensitive to the anion incorporation condition formed during the surface reconstruction process. Since antisite defects are potentially responsible for the inherent residual carrier concentrations and short carrier lifetimes, the optimization of anion incorporation conditions, by manipulating anion fluxes, anion species, and deposition temperature, was systematically studied. Optimization results are reported in the context of comparative studies on the influence of the growth temperature on the crystal structural quality and surface roughness performed under a designed set of deposition conditions. The optimized SL samples produced an overall strong photoresponse signal with a relatively sharp band edge that is essential for developing VLWIR detectors. A quantitative analysis of the lattice strain, performed at the atomic scale by aberration corrected transmission electron microscopy, provided valuable information about the strain distribution at the GaInSb-on-InAs interface and in the InAs layers, which was important for optimizing the anion conditions.},
   author = {G J Brown and H J Haugan and K Mahalingam and L Grazulis and S Elhamri},
   journal = {Quantum Sensing and Nanophotonic Devices Xii},
   title = {Impact of MBE deposition conditions on InAs/GaInSb superlattices for very long wavelength infrared detection},
   volume = {9370},
   year = {2015}
}
@article{Brune2012,
   abstract = {The prediction and experimental verification of the quantum spin Hall state marked the discovery of a new state of matter now known as topological insulators. Two-dimensional topological insulators exhibit the quantum spin-Hall effect, characterized by gapless spin-polarized counter-propagating edge channels. Whereas the helical character of these edge channels is now well established, experimental confirmation that the transport in the edge channels is spin polarized is still outstanding. We report experiments on nanostructures fabricated from HgTe quantum wells with an inverted band structure, in which a split gate technique allows us to combine both quantum spin Hall and metallic spin Hall transport in a single device. In these devices, the quantum spin Hall effect can be used as a spin current injector and detector for the metallic spin Hall effect, and vice versa, allowing for an all-electrical detection of spin polarization.},
   author = {C Brune and A Roth and H Buhmann and E M Hankiewicz and L W Molenkamp and J Maciejko and X L Qi and S C Zhang},
   issue = {6},
   journal = {Nat Phys},
   keywords = {wells},
   pages = {485-490},
   title = {Spin polarization of the quantum spin Hall edge states},
   volume = {8},
   year = {2012}
}
@article{Brune2010,
   abstract = {In the spin Hall effect, a current passed through a spin-orbit coupled electron gas induces a spin accumulation of inverse sign on either side of the sample. A number of possible mechanisms have been described, extrinsic as well as intrinsic ones, and they may occur in the ballistic as well as the diffusive transport regime. A central problem for experimentalists in studying the effect is the very small signals that result from the spin accumulation. Electrical measurements on metals have yielded reliable signatures of the spin Hall effect, but in semiconductors the spin accumulation could only be detected by optical techniques. Here we report experimental evidence for electrical manipulation and detection of the ballistic intrinsic spin Hall effect (ISHE) in semiconductors. We perform a non-local electrical measurement in nanoscale H-shaped structures built on high-mobility HgTe/(Hg, Cd)Te quantum wells. When the samples are tuned into the p-regime, we observe a large non-local resistance signal due to the ISHE, several orders of magnitude larger than in metals. In the n-regime, where the spin-orbit splitting is reduced, the signal is at least one order of magnitude smaller and vanishes for narrower quantum wells. We verify our experimental observations by quantum transport calculations.},
   author = {C Brune and A Roth and E G Novik and M Konig and H Buhmann and E M Hankiewicz and W Hanke and J Sinova and L W Molenkamp},
   issue = {6},
   journal = {Nat Phys},
   keywords = {quantum-wells
semiconductors
state},
   pages = {448-454},
   title = {Evidence for the ballistic intrinsic spin Hall effect in HgTe nanostructures},
   volume = {6},
   year = {2010}
}
@article{Bushell2017,
   author = {Z L Bushell and I P Marko and S J Sweeney and C S Kim and C D Merritt and W W Bewley and M V Warren and C L Canedy and I Vurgaftman and J R Meyer and M Kim},
   journal = {Proc Spie},
   title = {Pressure-dependent properties of type-II InAs/GaInSb mid-infrared interband cascade light-emitting devices (Conference Presentation)},
   volume = {10111},
   year = {2017}
}
@article{Buttiker2009,
   author = {M Buttiker},
   issue = {5938},
   journal = {Science},
   keywords = {hgte quantum-wells
backscattering
contacts
regime},
   pages = {278-279},
   title = {Edge-State Physics Without Magnetic Fields},
   volume = {325},
   year = {2009}
}
@article{Caldeira1981,
   author = {A O Caldeira and A J Leggett},
   issue = {4},
   journal = {Phys Rev Lett},
   pages = {211-214},
   title = {Influence of Dissipation on Quantum Tunneling in Macroscopic Systems},
   volume = {46},
   year = {1981}
}
@article{Campbell1991,
   abstract = {We describe the growth and characterization of the InAs/GaInSb superlattice on GaSb substrates. We present far-infrared (lambda approximately 10-mu-m) photoabsorption and photoconductivity spectra which are in good agreement with theoretical predictions for the photoresponse of this spatially indirect superlattice. We report time-resolved photoconductivity measurements in which two response times are observed. We interpret the fast, 2 ns decay as resulting from electron-hole recombination via deep defect levels and the slow, 2-mu-s decay as resulting from recombination of a small fraction of the photogenerated minority carriers which become trapped at a defect site.},
   author = {I H Campbell and I Sela and B K Laurich and D L Smith and C R Bolognesi and L A Samoska and A C Gossard and H Kroemer},
   issue = {7},
   journal = {Appl Phys Lett},
   keywords = {k-p theory
electronic-structure
detectors},
   pages = {846-848},
   title = {Far-Infrared Photoresponse of the Inas/Gainsb Superlattice},
   volume = {59},
   year = {1991}
}
@article{Cappello2011,
   abstract = {This paper presents the most recent results in theoretical/numerical studies on the physics of the quasi-helical regime in reversed field pinch (RFP) configurations. Such regime systematically characterizes RFX-mod experiments at high currents (I-p > 1.2 MA), producing clear internal electron transport barriers. Several approaches, ranging from a macroscopic (MHD) to a microscopic (transport) description, have been used to tackle the related complex physics. From the macroscopic point of view, we derive analytically the electrostatic velocity field consistent with a generic helical ohmic equilibrium. We also provide the first MHD initial-value simulation results in toroidal geometry obtained with the PIXIE3D code. Concerning transport, the effect of magnetic chaos healing by mode separatrix expulsion, believed to favour the formation of transport barriers, is discussed. Results indicate that helical equilibria originated by non-resonant modes are more resilient to chaos formation. Finally, gyrofluid and gyrokinetic tools have been used towards a first assessment of the role of microturbulence in the RFP. Concerning the electrostatic branches, ion temperature gradient mode stability is robustly improved in RFP with respect to tokamaks, due to stronger Landau damping effects, and the marginality condition is estimated to be only spottily reached in present experimental regimes, unless the effects of impurities are considered. Impurities, which in RFX-mod accumulate in the edge, may also significantly impact the stability of the impurity-driven modes. On the electromagnetic side, microtearing turbulence is found to probably play a role at the transport barriers.},
   author = {S Cappello and D Bonfiglio and D F Escande and S C Guo and I Predebon and F Sattin and M Veranda and P Zanca and C Angioni and L Chacon and J Q Dong and X Garbet and S F Liu},
   issue = {10},
   journal = {Nucl Fusion},
   keywords = {turbulent transport
microtearing modes
self-organization
ion turbulence
magnetic shear
kinetic-theory
tearing mode
plasmas
tokamaks
single},
   title = {Equilibrium and transport for quasi-helical reversed field pinches},
   volume = {51},
   year = {2011}
}
@article{Cardona1966,
   author = {M Cardona and F H Pollak},
   issue = {2},
   journal = {Phys Rev},
   pages = {530},
   title = {Energy-Band Structure of Germanium and Silicon - K.P Method},
   volume = {142},
   year = {1966}
}
@article{Chan1999,
   abstract = {We explore the characteristics of equilibrium tunneling of electrons from a 3D electrode into a high mobility 2D electron system. For most noninteger filing factors, we find that tunneling can be characterized by a single, well-defined tunneling rate. However, for spin-polarized quantum Hall states (nu = 1, 3, and 1/3) tunneling occurs at two distinct rates that differ by up to 2 orders of magnitude. The dependence of the two rates on temperature and tunnel barrier thickness suggests that slow in-plane spin relaxation creates a bottleneck for tunneling of electrons.},
   author = {H B Chan and R C Ashoori and L N Pfeiffer and K W West},
   issue = {16},
   journal = {Phys Rev Lett},
   keywords = {2-dimensional electron-gas
optically pumped nmr
level filling nu=1
magnetic-field
skyrmions
excitations
wells
gaas
integer},
   pages = {3258-3261},
   title = {Tunneling into ferromagnetic quantum Hall states: Observation of a spin bottleneck},
   volume = {83},
   year = {1999}
}
@article{Charpentier2013,
   abstract = {The two-dimensional topological insulator state in InAs/GaSb quantum wells manifests itself by topologically protected helical edge channel transport relying on an insulating bulk. This work investigates a way of suppressing bulk conductivity by using gallium source materials of different degrees of impurity concentrations. While highest-purity gallium is accompanied by clear conduction through the sample bulk, intentional impurity incorporation leads to a bulk resistance over 1 M Omega, independent of applied magnetic fields. In addition, ultra high electron mobilities for GaAs/AlGaAs structures fabricated in a molecular beam epitaxy system used for the growth of Sb-based samples are reported. (C) 2013 AIP Publishing LLC.},
   author = {C Charpentier and S Falt and C Reichl and F Nichele and A N Pal and P Pietsch and T Ihn and K Ensslin and W Wegscheider},
   issue = {11},
   journal = {Appl Phys Lett},
   keywords = {mobilities
gaas},
   pages = {112102},
   title = {Suppression of bulk conductivity in InAs/GaSb broken gap composite quantum wells},
   volume = {103},
   year = {2013}
}
@article{Chen2012,
   abstract = {The effect of magnetic field on electron transport in the inverted band structure of HgTe/CdTe quantum well is investigated. Although magnetic field breaks the time-reversal symmetry, the quantum spin Hall effect can still survive at large magnetic field up to 10 T. Moreover, two quantum anomalous Hall-like phases emerge, in which the system only has a spin-up or spin-down edge state at a given sample edge and the edge current is spin polarized. By tuning the Fermi energy, the system can transit between the quantum spin Hall phase and two quantum anomalous Hall-like phases, so the polarized direction of the edge current is well controllable. Thus the spin selectivity can be realized for potential applications of spintronics. Due to the quantum spin and anomalous Hall-like effects, the longitudinal and Hall resistances exhibit quantum plateaus. In addition, at certain magnetic field, some exotic plateaus like 2/3 fractional quantum Hall effect are also observed, where edge states with the same spin counterpropagate at the one edge. At last, these plateaus are hardly affected by Rashba spin-orbit interaction, Zeeman effect, and Anderson disorder.},
   author = {J C Chen and J Wang and Q F Sun},
   issue = {12},
   journal = {Phys Rev B},
   keywords = {single dirac cone
topological insulators
surface
bi2te3
phase},
   title = {Effect of magnetic field on electron transport in HgTe/CdTe quantum wells: Numerical analysis},
   volume = {85},
   year = {2012}
}
@article{Ciaccio2015,
   abstract = {The electrostatic response of the edge plasma to a magnetic island induced by resonant magnetic perturbations to the plasma edge of the circular limiter tokamak TEXTOR is analyzed. Measurements of plasma potential are interpreted by simulations with the Hamiltonian guiding center code ORBIT. We find a strong correlation between the magnetic field topology and the poloidal modulation of the measured plasma potential. The ion and electron drifts yield a predominantly electron driven radial diffusion when approaching the island X-point while ion diffusivities are generally an order of magnitude smaller. This causes a strong radial electric field structure pointing outward from the island O-point. The good agreement found between measured and modeled plasma potential connected to the enhanced radial particle diffusivities supports that a magnetic island in the edge of a tokamak plasma can act as convective cell. We show in detail that the particular, non-ambipolar drifts of electrons and ions in a 3D magnetic topology account for these effects. An analytical model for the plasma potential is implemented in the code ORBIT, and analyses of ion and electron radial diffusion show that both ion-and electron-dominated transport regimes can exist, which are known as ion and electron root solutions in stellarators. This finding and comparison with reversed field pinch studies and stellarator literature suggest that the role of magnetic islands as convective cells and hence as major radial particle transport drivers could be a generic mechanism in 3D plasma boundary layers.},
   author = {G Ciaccio and O Schmitz and G Spizzo and S S Abdullaev and T E Evans and H Frerichs and R B White},
   issue = {10},
   journal = {Phys Plasmas},
   keywords = {dynamic ergodic divertor
radial electric-field
transport
tokamak
operation
vicinity
design
model},
   title = {Helical modulation of the electrostatic plasma potential due to edge magnetic islands induced by resonant magnetic perturbation fields at TEXTOR},
   volume = {22},
   year = {2015}
}
@article{Cooper1998,
   abstract = {We observe large resistance increases in a crossed band-gap electron-hole system owing to a coupling-induced energy gap at the point of anticrossing between the electron and hole dispersion relations. Samples with various degrees of coupling have been fabricated with front and back gates, which are able to deplete completely the electrons or holes, respectively. This has enabled a systematic study of the electron-hole coupling as a function of the total charge in the system. These results are interpreted in the light of recent theoretical predictions about two-dimensional electron-hole systems and equivalent experimental work on strongly coupled double two-dimensional electron gases. The temperature dependence of the coupling-induced resistance enhancement of the material has also been investigated, allowing us to obtain the magnitude of the resultant energy gap in the dispersion relations, which is found to be approximately 2 meV in the sample with the strongest coupling. [S0163-1829(98)02119-5].},
   author = {L J Cooper and N K Patel and V Drouot and E H Linfield and D A Ritchie and M Pepper},
   issue = {19},
   journal = {Phys Rev B},
   keywords = {quantum-wells
field
system},
   pages = {11915-11918},
   title = {Resistance resonance induced by electron-hole hybridization in a strongly coupled InAs/GaSb/AlSb heterostructure},
   volume = {57},
   year = {1998}
}
@article{Sarma2013,
   abstract = {We theoretically consider the carrier density dependence of low-temperature electrical conductivity in highquality and low-disorder two-dimensional (2D) "metallic" electronic systems such as 2D GaAs electron or hole quantum wells or doped/gated graphene. Taking into account resistive scattering by Coulomb disorder arising from quenched random charged impurities in the environment, we show that the 2D conductivity sigma(n) varies as sigma similar to n(beta(n)) as a function of the 2D carrier density n where the exponent beta(n) is a smooth, but nonmonotonic, function of density n with possible nontrivial extrema. In particular, the density scaling exponent beta(n) depends qualitatively on whether the Coulomb disorder arises primarily from remote or background charged impurities or short-range disorder and can, in principle, be used to characterize the nature of the dominant background disorder. A specific important prediction of the theory is that for resistive scattering by remote charged impurities, the exponent beta can reach a value as large as 2.7 for k(F)d similar to 1, where k(F) similar to root n is the 2D Fermi wave vector and d is the separation of the remote impurities from the 2D layer. Such an exponent beta (>5/2) is surprising because unscreened Coulomb scattering by remote impurities gives a limiting theoretical scaling exponent of beta = 5/2, and naively one would expect beta(n) <= 5/2 for all densities since unscreened Coulomb scattering should nominally be the situation bounding the resistive scattering from above. We find numerically and show theoretically that the maximum value of alpha (beta), the mobility (conductivity) exponent, for 2D semiconductor quantum wells is around 1.7 (2.7) for all values of d (and for both electrons and holes) with the maximum a occurring around k(F)d similar to 1. We discuss experimental scenarios for the verification of our theory.},
   author = {S Das Sarma and E H Hwang},
   issue = {3},
   journal = {Phys Rev B},
   keywords = {metal-insulator-transition
semiconductor quantum-wells
charged-impurity-scattering
silicon inversion-layers
molecular-beam epitaxy
electron-gas
2 dimensions
alxga1-xas/gaas heterojunctions
gaas/algaas heterostructures
residual resistivity},
   pages = {35439},
   title = {Universal density scaling of disorder-limited low-temperature conductivity in high-mobility two-dimensional systems},
   volume = {88},
   year = {2013}
}
@article{de-Leon1999,
   abstract = {We calculate here the energy spectrum of InAs/GaSb heterostructure taking into account a complicated, anisotropic, and nonparabolic structure of the valence band of GaSb. In InAs/GaSb heterostructures the valence band of the GaSb layer overlaps with the conduction band of the InAs layer. The electrons in the Inks layer are coupled to the holes in the GaSb layer and a hybridization gap is formed. The coupling is considered here as a small perturbation for the problem of two decoupled infinite quantum wells, one of holes and one of electrons. The band structure of the coupled system shows features that result from anisotropy, dependence of the coupling on the in-plane vector, and lifting of the double degeneracy of the energy bands of electrons and holes due to the coupling. The splitting of the energy bands is very important at the crossing point. Interesting results of these effects are the possibility of a new kind of a gapless state and nontrivial constant energy contours. [S0163-1829(99)02027-5].},
   author = {S de-Leon and L D Shvartsman and B Laikhtman},
   issue = {3},
   journal = {Phys Rev B},
   keywords = {electron-hole system
cyclotron-resonance oscillations
excitonic ground-state
gasb
transition
field
heterostructures
hybridization
superlattices
interfaces},
   pages = {1861-1870},
   title = {Band structure of coupled InAs/GaSb quantum wells},
   volume = {60},
   year = {1999}
}
@article{Sarma1985,
   author = {S Das Sarma and F Stern},
   issue = {12},
   journal = {Phys Rev B},
   pages = {8442-8444},
   title = {Single-Particle Relaxation-Time Versus Scattering Time in an Impure Electron-Gas},
   volume = {32},
   year = {1985}
}
@article{Dier2004,
   abstract = {A series of wet-chemical etchants for materials lattice-matched to GaSb was investigated. The etch rates for GaSb, AlAsSb, InAsSb and InAs with etch solutions based on KNa-tartaric acid (C4H4KNaO6), citric acid (C6H8O7) and hydrochloric acid were determined and the selectivities for the four different etching solutions are shown. The applicability of the selectivity between GaSb and InAs (respectively InAsSb) with C4H4KNaO6:HCl:H2O2:H2O (selectivity higher than 15:1) and C6H8O7:H2O2 (selectivity around 1:100) is proved by a substrate removal experiment. Also a new etchant for AlAsSb is proposed: HCl:H2O:H2O etches AlAsSb versus GaSb with a selectivity of 5:1 and the GaSb surface underneath is smooth and without any remaining particles of oxidized aluminium.},
   author = {O Dier and C Lin and M Grau and M C Amann},
   issue = {11},
   journal = {Semicond Sci Tech},
   keywords = {quantum-well laser
mu-m
low-threshold
fabrication
devices
diodes
inas},
   pages = {1250-1253},
   title = {Selective and non-selective wet-chemical etchants for GaSb-based materials},
   volume = {19},
   year = {2004}
}
@article{Dingle1952,
   author = {R B Dingle},
   issue = {1107},
   journal = {Proc R Soc Lon Ser-A},
   pages = {517-525},
   title = {Some Magnetic Properties of Metals .2. The Influence of Collisions on the Magnetic Behaviour of Large Systems},
   volume = {211},
   year = {1952}
}
@misc{Drndic1995,
   author = {Marija Drndic},
   institution = {University of Cambridge},
   title = {Transport Properties of InAs/Ga(Al)Sb Single Electron and Double Electron-Hole QWs},
   year = {1995}
}
@article{Du2015,
   abstract = {We have engineered electron-hole bilayers of inverted InAs/GaSb quantum wells, using dilute silicon impurity doping to suppress residual bulk conductance. We have observed robust helical edge states with wide conductance plateaus precisely quantized to 2e(2)/h in mesoscopic Hall samples. On the other hand, in larger samples the edge conductance is found to be inversely proportional to the edge length. These characteristics persist in a wide temperature range and show essentially no temperature dependence. The quantized plateaus persist to a 12 T applied in-plane field; the conductance increases from 2e(2)/h in strong perpendicular fields manifesting chiral edge transport. Our study presents a compelling case for exotic properties of a one-dimensional helical liquid on the edge of InAs/GaSb bilayers.},
   author = {L J Du and I Knez and G Sullivan and R R Du},
   issue = {9},
   journal = {Phys Rev Lett},
   keywords = {hgte quantum-wells
topological insulators
hybridization
systems
absence},
   pages = {96802},
   title = {Robust Helical Edge Transport in Gated InAs/GaSb Bilayers},
   volume = {114},
   year = {2015}
}
@article{Du2017,
   abstract = {We report on a class of quantum spin Hall insulators (QSHIs) in strained-layer InAs/GaInSb quantum wells, in which the bulk gaps are enhanced up to fivefold as compared to the binary InAs/GaSb QSHI. Remarkably, with consequently increasing edge velocity, the edge conductance at zero and applied magnetic fields manifests time reversal symmetry-protected properties consistent with the Z(2) topological insulator. The InAs/GaInSb bilayers offer a much sought-after platform for future studies and applications of the QSHI.},
   author = {L J Du and T X Li and W K Lou and X J Wu and X X Liu and Z D Han and C Zhang and G Sullivan and A Ikhlassi and K Chang and R R Du},
   issue = {5},
   journal = {Phys Rev Lett},
   keywords = {topological insulators
phase-transition
wells},
   pages = {56803},
   title = {Tuning Edge States in Strained-Layer InAs/GaInSb Quantum Spin Hall Insulators},
   volume = {119},
   year = {2017}
}
@article{Dupont1998,
   abstract = {We demonstrate the cascade process in mid-infrared electroluminescent InAs/GaInSb/AlSb multi-quantum-well devices. We report the proportional relation between the emitted optical power and the number of periods. This observed scaling is associated with the sequential transport of electrons from one active region to the next situated downstream in potential energy through the injection region. Deviations from this exact scaling are correlated with the variation of the wafer-to-wafer structural quality. (C) 1998 American Institute of Physics.},
   author = {E Dupont and J P McCaffrey and H C Liu and M Buchanan and R Q Yang and C H Lin and D Zhang and S S Pei},
   issue = {12},
   journal = {Appl Phys Lett},
   keywords = {well diode-lasers
carrier lifetimes
quantum
detectors},
   pages = {1495-1497},
   title = {Demonstration of cascade process in InAs/GaInSb/AlSb mid-infrared light emitting devices},
   volume = {72},
   year = {1998}
}
@article{Dyakonov2008,
   author = {M I Dyakonov},
   journal = {Springer Ser Solid-S},
   keywords = {nuclear magnetic-resonance
two-dimensional electrons
dynamic polarization
relaxation
heterostructures
crystals
photocurrent
orientation
saturation
anisotropy},
   pages = {1-28},
   title = {Basics of Semiconductor and Spin Physics},
   volume = {157},
   year = {2008}
}
@article{Dyksik2016,
   abstract = {Optical properties of AlSb/InAs/GaInSb/InAs/AlSb quantum wells (QWs) grown on an InAs substrate were investigated from the point of view of room temperature emission in the mid-and long-wavelength infrared ranges. By means of two independent techniques of optical spectroscopy, photoreflectance and temperature-dependent photoluminescence, it was proven that the main process limiting the performance of such InAs substrate-based type II structures is related to the escape of carriers from the hole ground state of the QW. Two nonradiative recombination channels were identified. The main process was attributed to holes tunneling to the valence band of the GaAsSb spacing layer and the second one with trapping of holes by native defects located in the same layer.},
   author = {M Dyksik and M Motyka and M Kurka and K Ryczko and M Dallner and S Hofling and M Kamp and G Sek and J Misiewicz},
   issue = {8},
   journal = {Opt Quant Electron},
   keywords = {fourier-transform spectroscopy
mid-infrared photoluminescence
type ii quantum wells
localized states
interband cascade lasers
quantum-wells
mu-m},
   title = {Photoluminescence quenching mechanisms in type II InAs/GaInSb QWs on InAs substrates},
   volume = {48},
   year = {2016}
}
@article{Dyksik2017,
   abstract = {Two designs of active region for an interband cascade laser, based on double or triple GaInSb/InAs type II quantum wells (QWs), were compared with respect to passive mode-locked operation in the mid-infrared range around 4 mu m. The layer structure and electron and hole wavefunctions under external electric field were engineered to allow controlling the optical transition oscillator strength and the resulting lifetimes. As a result, the investigated structures can mimic absorber-like and gain-like sections of a mode-locked device when properly polarized with opposite bias. A significantly larger oscillator strength tuning range for triple QWs was experimentally verified by Fourier-transform photoreflectance. (C) 2017 The Japan Society of Applied Physics},
   author = {M Dyksik and M Motyka and M Kurka and K Ryczko and J Misiewicz and A Schade and M Kamp and S Hofling and G Sek},
   issue = {11},
   journal = {Jpn J Appl Phys},
   keywords = {modulation spectroscopy
mu-m
semiconductors},
   title = {Electrical tuning of the oscillator strength in type II InAs/GaInSb quantum wells for active region of passively mode-locked interband cascade lasers},
   volume = {56},
   year = {2017}
}
@article{Dyksik2015,
   abstract = {The spatial uniformity of GaSb- and InAs substrate-based structures containing type II quantum wells was probed by means of large-scale photoluminescence (PL) mapping realized utilizing a Fourier transform infrared spectrometer. The active region was designed and grown in a form of a W-shaped structure with InAs and GaInSb layers for confinement of electrons and holes, respectively. The PL spectra were recorded over the entire 2-in. wafers, and the parameters extracted from each spectrum, such as PL peak energy position, its linewidth and integrated intensity, were collected in a form of two-dimensional spatial maps. Throughout the analysis of these maps, the wafers' homogeneity and precision of the growth procedure were investigated. A very small variation of PL peak energy over the wafer indicates InAs quantum well width fluctuation of only a fraction of a monolayer and hence extraordinary thickness accuracy, a conclusion further supported by high uniformity of both the emission intensity and PL linewidth.},
   author = {M Dyksik and M Motyka and G Sek and J Misiewicz and M Dallner and R Weih and M Kamp and S Hofling},
   journal = {Nanoscale Res Lett},
   keywords = {spatially resolved photoluminescence
type ii quantum wells
mid-infrared
fourier transform spectroscopy
interband cascade lasers},
   pages = {1-7},
   title = {Submonolayer Uniformity of Type II InAs/GaInSb W-shaped Quantum Wells Probed by Full-Wafer Photoluminescence Mapping in the Mid-infrared Spectral Range},
   volume = {10},
   year = {2015}
}
@article{Eaglesham1991,
   abstract = {Heteroepitaxial MBE growth of Ge on Si(100) is studied at temperatures down to room temperature.  We show that, as for Si and GaAs homoepitaxy, the low-temperature limit to growth is an epitaxial thickness, h(epi), before the amorphous phase is nucleated.  h(epi) increases with increasing temperature with an apparent activation energy of 0.5 +/- 0.1 eV at 0.2 angstrom/s.  Above 170-degrees-C h(epi) increases discontinuously and becomes effectively infinite, possibly as solid phase begins to occur.  We show that growth is planar for all temperatures below 300-degrees-C, so that low-temperature growth can be used near 200-degrees-C to suppress island formation without encountering the limited thickness effect.  In contrast with planar growth at high temperatures with an As "surfactant", strain relaxation of these planar epilayers occurs by normal dislocation introduction to give an array of predominantly edge misfit dislocations.},
   author = {D J Eaglesham and M Cerullo},
   issue = {20},
   journal = {Appl Phys Lett},
   keywords = {molecular-beam-epitaxy
silicon
implantation
strain
layers},
   pages = {2276-2278},
   title = {Low-Temperature Growth of Ge on Si(100)},
   volume = {58},
   year = {1991}
}
@article{Eich2000,
   abstract = {An important operational range for TEXTOR-DED is title case of a high ergodization at the plasma edge. Under these conditions, the edge magnetic field forms a proper ergodic layer and a laminar zone. The laminar zone is established by magnetic field lines which intersect wall elements after only a few toroidal turns (open ergodic system). For this, both the heat and particle transport in the plasma edge are dominated by the laminar zone which shows a well defined structure compared with that of the ergodic layer. For the present analysis the regions containing field lines with connection lengths corresponding to one or to two poloidal turns are of particular interest; the radial width of these regions is of the same order as the width of the unperturbed SOL of a 'classical' limiter or divertor configuration. Field lines running poloidally twice around the torus introduce a particular new feature, they impose a connection between radially separated areas and thus enhance the radial temperature and particle transport. A new 2-D modelling approach code for the laminar zone of an ergodic divertor has been developed which is strongly oriented on the topology of the magnetic field lines in the plasma edge. A 2-D finite element method is used in order to model the perpendicular transport of particles and energy. For obtaining a solution of the parallel transport, an analytical model is discussed providing expressions for averaged particle and energy sources. By considering the topological properties of the magnetic field and corresponding assumptions in the code, the transport calculation in the perturbed plasma edge gives a first insight into the generic transport properties of the TEXTOR-DED laminar zone. As an important application for later experiments the power fluxes to the wall elements are estimated. They show a strong variation perpendicular to the perturbation coils and a medium variation over the helical divertor footprints.},
   author = {T Eich and D Reiser and K H Finken},
   issue = {10},
   journal = {Nucl Fusion},
   keywords = {near-field divertor
ergodic divertor
tokamaks
layer},
   pages = {1757-1772},
   title = {Two dimensional modelling approach to transport properties of the TEXTOR-DED laminar zone},
   volume = {40},
   year = {2000}
}
@book{,
   author = {J W Ekin},
   keywords = {Low temperatures Measurement.
Low temperatures Instruments.
Low temperature research.
Superconductors.},
   pages = {6-704},
   publisher = {Oxford University Press},
   title = {Experimental techniques for low-temperature measurements }
}
@article{Elkenany2015,
   abstract = {In this paper we explore the effects of temperature on the electronic and mechanical properties of GaSb and AlSb semiconductors by using the local empirical pseudo-potential method. Our results show that the band gaps, refractive index, optical dielectric constant, elastic constants (C-11, C-12, C-44), bulk modulus, shear modulus and Young modulus of these compounds vary with the change in temperature. The comparison of some of our results with the available experimental data confirms the accurateness of our theoretical approach, which also infers the reliability of our other theoretical results. As, for some of the present calculations a little experimental data is available for comparison, therefore these results can be used as a reference work in the future studies. (c) 2015 Elsevier B.V. All rights reserved.},
   author = {E B Elkenany},
   journal = {Spectrochim Acta A},
   keywords = {electronic properties
optical properties
mechanical properties
semiconductors
energy-gap
refractive-index
band-structure
pseudopotential calculations
hydrostatic-pressure
elastic properties
binary compounds
alloys
dependence
gaas},
   pages = {15-20},
   title = {Theoretical investigations of electronic, optical and mechanical properties for GaSb and AlSb semiconductors under the influence of temperature},
   volume = {150},
   year = {2015}
}
@article{Elliott1954,
   author = {R J Elliott},
   issue = {2},
   journal = {Phys Rev},
   pages = {266-279},
   title = {Theory of the Effect of Spin-Orbit Coupling on Magnetic Resonance in Some Semiconductors},
   volume = {96},
   year = {1954}
}
@article{Engels1997,
   abstract = {Spin splitting of conduction-band energy levels in a modulation-doped InP/In0.77Ga0.23As/InP quantum well has been studied by Shubnikov-de Haas oscillations. By analyzing the characteristic beating pattern of the oscillations the coupling constant alpha for spin-orbit interaction was determined. Biasing a gate on top of a Hall bat was used to modify the strength of the spin-orbit coupling. The measured spin-orbit coupling parameter alpha is quantitatively explained by utilizing a refined envelope-function-approximation theory for heterostructures.},
   author = {G Engels and J Lange and T Schapers and H Luth},
   issue = {4},
   journal = {Phys Rev B},
   keywords = {heterostructures},
   pages = {R1958-R1961},
   title = {Experimental and theoretical approach to spin splitting in modulation-doped In_xGa_1-xAs/InP quantum wells for B approaching 0},
   volume = {55},
   year = {1997}
}
@article{Englert1983,
   author = {T Englert and J C Maan and D C Tsui and A C Gossard},
   issue = {11},
   journal = {Solid State Commun},
   pages = {989-991},
   title = {A Study of Intersubband Scattering in GaAs-Al_xGa_1-xAs Heterostructures by Means of a Parallel Magnetic-Field},
   volume = {45},
   year = {1983}
}
@article{Essert2015,
   abstract = {To understand the seemingly absent temperature dependence in the conductance of two-dimensional topological insulator edge states, we perform a numerical study which identifies the quantitative influence of the combined effect of dephasing and elastic scattering in charge puddles close to the edges. We show that this mechanism may be responsible for the experimental signatures in HgTe/CdTe quantum wells if the puddles in the samples are large and weakly coupled to the sample edges. We propose experiments on artificial puddles which allow one to verify this hypothesis and to extract the real dephasing time scale using our predictions. In addition, we present a method to include the effect of dephasing in wave-packet-time-evolution algorithms.},
   author = {S Essert and V Krueckl and K Richter},
   issue = {20},
   journal = {Phys Rev B},
   keywords = {hgte quantum-wells},
   title = {Two-dimensional topological insulator edge state backscattering by dephasing},
   volume = {92},
   year = {2015}
}
@article{Ezawa2015,
   abstract = {We report the recent progress on the theoretical aspects of monolayer topological insulators including silicene, germanene and stanene, which are monolayer honeycomb structures of silicon, germanium and tin, respectively. They show quantum spin Hall effects in nature due to the spin-orbit interaction. The band gap can be tuned by applying perpendicular electric field, which induces a topological phase transition. We also analyze the topological properties of generic honeycomb systems together with the classification of topological insulators. Phase diagrams of topological insulators and superconductors in honeycomb systems are explicitly determined. We also investigate topological electronics including a topological field-effect transistor, the topological Kirchhoff's law and the topological spin-valleytronics.},
   author = {M Ezawa},
   issue = {12},
   journal = {J Phys Soc Jpn},
   keywords = {massless dirac fermions
majorana fermions
electronic-properties
edge excitations
phase-transition
chern numbers
valley-chern
graphene
superconductor
field},
   title = {Monolayer Topological Insulators: Silicene, Germanene, and Stanene},
   volume = {84},
   year = {2015}
}
@article{Fang1988,
   author = {F F Fang and T P Smith and S L Wright},
   issue = {1-3},
   journal = {Surf Sci},
   pages = {310-315},
   title = {Landau-Level Broadening and Scattering Time in Modulation Doped GaAs/AlGaAs Heterostructures},
   volume = {196},
   year = {1988}
}
@book{,
   abstract = {Modern electronics is being transformed as device size decreases to a size where the dimensions are significantly smaller than the constituent electron's mean free path. In such systems the electron motion is strongly confined resulting in dramatic changes of behaviour compared to the bulk. This book introduces the physics and applications of transport in such mesoscopic and nanoscale electronic systems and devices. The behaviour of these novel devices is influenced by numerous effects not seen in bulk semiconductors, such as the Aharonov-Bohm Effect, disorder and localization, energy quantization, electron wave interference, spin splitting, tunnelling and the quantum hall effect to name a few. Including coverage of recent developments, and with a chapter on carbon-based nanoelectronics, this book will provide a good course text for advanced students or as a handy reference for researchers or those entering this interdisciplinary area.},
   author = {David K Ferry and Institute of Physics (Great Britain)},
   keywords = {Electron transport.
Semiconductors.
Nanostructured materials Electric properties.
Nanostructures Electric properties.
Mesoscopic phenomena (Physics)
Electronic books.},
   pages = {(Various Pagings)},
   title = {Transport in semiconductor mesoscopic devices}
}
@article{Fert2001,
   abstract = {We adapt the spin accumulation model of the perpendicular transport in metallic magnetic multilayers to the issue of spin injection from a ferromagnetic metal (F) into a semiconductor (N). We show that the problem of the conductivity mismatch between F and N can be solved by introducing a spin dependent inter-face resistance (tunnel junction preferably) at the F/N interfaces. In the case of a F/N/F structure, a significant value of the magnetoresistance can be obtained if the junction resistance at the F/N and N/F interfaces is chosen between two threshold values depending on the resistivity, spin diffusion length and thickness of N. The problem is treated for various geometries (vertical or lateral F/N/F structures).},
   author = {A Fert and H Jaffres},
   issue = {18},
   journal = {Phys Rev B},
   keywords = {gallium-arsenide
magnetoresistance
multilayers
nanowires
films},
   pages = {184420},
   title = {Conditions for efficient spin injection from a ferromagnetic metal into a semiconductor},
   volume = {64},
   year = {2001}
}
@article{FinnemorDk1966,
   author = {Finnemor.Dk and Stromber.Tf and C A Swenson},
   issue = {1},
   journal = {Phys Rev},
   pages = {231-+},
   title = {Superconducting Properties of High-Purity Niobium},
   volume = {149},
   year = {1966}
}
@article{Gallagher2006,
   abstract = {This paper reviews the remarkable developments of the magnetic tunnel junction over the last decade and in particular, work aimed at demonstrating its potential for a dense, fast, and nonvolatile random access memory. The initial focus is on the technological roots of the magnetic tunnel junction, and then on the recent progress made with engineered materials for this device. Following that, we discuss the development of the magnetic random access memory (MRAM) technology, in which the magnetic tunnel Junction serves as both the storage device and the storage sensing device. The emphasis is on work at IBM, including demonstrations of basic capabilities of the technology and work on a 16-Mb '' product demonstrator '' design in 180-nm node technology, which was targeted to be a realistic test bed for the MRAM technology. Performance and cost are compared with those of competing technologies. The paper also serves as an introduction to more specialized papers in this issue on MRAM device physics, magnetic tunnel junction materials and device characterization, MRAM processing, and MRAM design.},
   author = {W J Gallagher and S S P Parkin},
   issue = {1},
   journal = {Ibm J Res Dev},
   keywords = {random-access memory
room-temperature
giant magnetoresistance
ferromagnetic-films
technology
multilayers
devices
lithography
stability
barriers},
   pages = {5-23},
   title = {Development of the magnetic tunnel junction MRAM at IBM: From first junctions to a 16-Mb MRAM demonstrator chip},
   volume = {50},
   year = {2006}
}
@article{Ganichev2004,
   abstract = {The relative strengths of Rashba and Dresselhaus terms describing the spin-orbit coupling in semiconductor quantum well (QW) structures are extracted from photocurrent measurements on n-type InAs QWs containing a two-dimensional electron gas (2DEG). This novel technique makes use of the angular distribution of the spin-galvanic effect at certain directions of spin orientation in the plane of a QW. The ratio of the relevant Rashba and Dresselhaus coefficients can be deduced directly from experiment and does not relay on theoretically obtained quantities. Thus our experiments open a new way to determine the different contributions to spin-orbit coupling.},
   author = {S D Ganichev and V V Bel'kov and L E Golub and E L Ivchenko and P Schneider and S Giglberger and J Eroms and J De Boeck and G Borghs and W Wegscheider and D Weiss and W Prettl},
   issue = {25},
   journal = {Phys Rev Lett},
   keywords = {relaxation anisotropy
inversion asymmetry
interface asymmetry
orbit interaction
electron-gas
heterostructures
subband
orientation
systems},
   pages = {256601},
   title = {Experimental separation of Rashba and Dresselhaus spin splittings in semiconductor quantum wells},
   volume = {92},
   year = {2004}
}
@article{Ganichev2014,
   abstract = {The paper reviews the interplay of Rashba/Dresselhaus spin splittings in various two-dimensional systems made of zinc-blende III-V, wurtzite, and SiGe semiconductors. We discuss the symmetry aspects of the linear and cubic in electron wavevector spin splitting in heterostructures prepared on (001)-, (110)-, (111)-, (113)-, (112)-, and (013)-oriented substrates and address the requirements for suppression of spin relaxation and realization of the persistent spin helix state. In experimental part of the paper, we overview experimental results on the interplay of Rashba/Dresselhaus spin splittings probed by photogalvanic spectroscopy: The method based on the phenomenological equivalence of the linear-in-wavevector spin splitting and several photogalvanic phenomena.},
   author = {S D Ganichev and L E Golub},
   issue = {9},
   journal = {Phys Status Solidi B},
   keywords = {photogalvanics
rashba/dresselhaus spin splittings
semiconductors
semiconductor quantum-wells
2-dimensional electron-gas
field-effect transistors
tunneling ionization
weak-localization
band excitation
conduction-band
magnetic-field
relaxation anisotropy
interface asymmetry},
   pages = {1801-1823},
   title = {Interplay of Rashba/Dresselhaus spin splittings probed by photogalvanic spectroscopy - A review},
   volume = {251},
   year = {2014}
}
@article{Giglberger2007,
   abstract = {The spin-galvanic effect and the circular photogalvanic effect induced by terahertz radiation are applied to determine the relative strengths of Rashba and Dresselhaus band spin splitting in (001)-grown GaAs and InAs based two dimensional electron systems. We observed that shifting the delta-doping plane from one side of the quantum well to the other results in a change of sign of the photocurrent caused by Rashba spin splitting while the sign of the Dresselhaus term induced photocurrent remains. The measurements give the necessary feedback for technologists looking for structures with equal Rashba and Dresselhaus spin splittings or perfectly symmetric structures with zero Rashba constant.},
   author = {S Giglberger and L E Golub and V V Bel'kov and S N Danilov and D Schuh and C Gerl and F Rohlfing and J Stahl and W Wegscheider and D Weiss and W Prettl and S D Ganichev},
   issue = {3},
   journal = {Phys Rev B},
   keywords = {relaxation anisotropy
heterostructures
systems},
   title = {Rashba and Dresselhaus spin splittings in semiconductor quantum wells measured by spin photocurrents},
   volume = {75},
   year = {2007}
}
@article{Goran2004,
   abstract = {Magnetotransport properties of a 2D electron gas in narrow GaAs quantum wells with AlAs/GaAs superlattice barriers were studied. It is shown that the anisotropic positive magnetoresistance observed in selectively doped semiconductor structures in a parallel magnetic field is caused by the spatial modulation of the 2D electron gas. (C) 2004 MAIK "Nauka / Interperiodica".},
   author = {A V Goran and A A Bykov and A K Bakarov and J C Portal},
   issue = {10},
   journal = {Jetp Lett+},
   keywords = {transport},
   pages = {495-498},
   title = {Anisotropic positive magnetoresistance of a nonplanar 2D electron gas in a parallel magnetic field},
   volume = {79},
   year = {2004}
}
@article{Goran2008,
   abstract = {The magnetoresistance of a 2D electron gas was investigated in non-planar GaAs quantum wells with different degrees of non-planarity. We observed the anisotropic positive magnetoresistance of the 2D electron gas, and found it to depend on both the current direction and orientation of the in-plane magnetic field. We claim that this magnetoresistance could be explained by classical scattering of 2D electrons moving in a non-uniform effective magnetic field, originating from the non-planar character of quantum wells.},
   author = {A V Goran and A A Bykov and A I Toropov},
   issue = {10},
   journal = {Semicond Sci Tech},
   keywords = {metal-insulator-transition
dimensions
transport
systems
layers
phase
gaas},
   pages = {105017},
   title = {Classical anisotropic magnetoresistance of a non-planar 2D electron gas in a parallel magnetic field},
   volume = {23},
   year = {2008}
}
@article{Grein2002,
   abstract = {The optimal performance of VLWIR (15um cutoff wavelength) photovoltaic detectors is assessed theoretically. The electronic band structures are computed with a fourteen-band restricted-basis envelope function Hamiltonian that includes terms coupling heavy and light holes at the superlattice interfaces. These terms describe the type of bonding at the interfaces (InSb or GaAs-like) and result in approximately 25 meV energy gap corrections in thin superlattices in comparison with conventional envelope-function approaches that neglect these terms. Auger lifetimes and upper bounds to detector detectivities are computed with these accurate band structures. The Auger transition rate calculations include Umklapp terms in the transition amplitude.},
   author = {C H Grein and W H Lau and T L Harbert and M E Flatte},
   journal = {Materials for Infrared Detectors Ii},
   keywords = {infrared detector
superlattice
band engineering
algasb
inas
ingasb
alsb},
   pages = {39-43},
   title = {Modeling of very long infrared wavelength InAs/GaInSb strained layer superlattice detectors},
   volume = {4795},
   year = {2002}
}
@article{Grundler2000,
   abstract = {We report on zero-field spin splitting of two-dimensional electron systems. Though absent in the unbiased InAs square asymmetric quantum well (SAQW), the Rashba splitting becomes pronounced by applying a positive back-gate voltage. In our SAQW, the Rashba parameter ct increases with electron density and is tuned by a factor of about 2 using an additional front gate without charging the well. We argue that the band-edge profile provides the important contribution for spin-orbit interaction due to barrier penetration of the envelope wave function. This mechanism can provide the potential for high speed implementation in spintronics.},
   author = {D Grundler},
   issue = {26},
   journal = {Phys Rev Lett},
   keywords = {spin-orbit interaction
field
heterostructure
oscillations
asymmetry
subband},
   pages = {6074-6077},
   title = {Large Rashba splitting in InAs quantum wells due to electron wave function penetration into the barrier layers},
   volume = {84},
   year = {2000}
}
@article{Gul2017,
   abstract = {Large scale fabrication using Complementary Metal Oxide Semiconductor compatible technology of semiconductor nanostructures that operate on the principles of quantum transport is an exciting possibility now due to the recent development of ultra-high mobility hole gases in epitaxial germanium grown on standard silicon substrates. We present here a ballistic transport study of patterned surface gates on strained Ge quantum wells with SiGe barriers, which confirms the quantum characteristics of the Ge heavy hole valence band structure in 1-dimension. Quantised conductance at multiples of 2e(2)/h is a universal feature of hole transport in Ge up to 10 x (2e(2)/h). The behaviour of ballistic plateaus with finite source-drain bias and applied magnetic field is elucidated. In addition, a reordering of the ground state is observed. Published by AIP Publishing.},
   author = {Y Gul and S N Holmes and P J Newton and D J P Ellis and C Morrison and M Pepper and C H W Barnes and M Myronov},
   issue = {23},
   journal = {Appl Phys Lett},
   keywords = {point-contact
electron-gas
heterostructures},
   pages = {233512},
   title = {Quantum ballistic transport in strained epitaxial germanium},
   volume = {111},
   year = {2017}
}
@article{Gumbs2004,
   abstract = {We consider the effect of spin-orbit (SO) coupling on the plasma oscillations for a coupled system of two-dimensional electron or heavy hole (HH) gases. The Rashba effect lifts the degeneracy of the energy spectrum and produces a linear term for electrons but a cubic term for HH states in wave vector space. The SO coupling gives rise to two plasmon branches for a single layer due to transitions within a subband and between subbands. The interlayer coupling splits each of these branches. We present numerical results for the frequency of the collective excitations as a function of wave vector and the Rashba parameter. The application to optical characterization studies is discussed. (C) 2004 American Institute of Physics.},
   author = {G Gumbs},
   issue = {14},
   journal = {Appl Phys Lett},
   keywords = {spin-orbit interaction
2-dimensional electron
quantum-wells
systems
layers},
   pages = {2821-2823},
   title = {Rashba effect on the plasma oscillations in a coupled bilayer of electrons and holes},
   volume = {85},
   year = {2004}
}
@book{H1989,
   author = {Marian A H. and Helmut S.},
   keywords = {Molecular beam epitaxy.},
   pages = {1-20},
   publisher = {Springer},
   title = {Molecular beam epitaxy : fundamentals and current status},
   year = {1989}
}
@article{Hai1996,
   abstract = {The effects due to intersubband coupling and screening on the ionized impurity scattering are studied for a quasi-two-dimensional electron system in delta-doped semiconductors. We found that intersubband coupling plays an essential role in describing the screening properties and the effect of ionized impurity scattering on the mobility in a multisubband system. At the onset of the occupation of a higher subband, the screening due to the intersubband coupling leads to a reduction of the small angle scattering rate in the lower subband. We showed that such an effect is significant in a delta-doped quantum well and results in a pronounced increase of the quantum mobility at the onset of the occupation of a higher subband. (C) 1996 American Institute of Physics.},
   author = {G Q Hai and N Studart and F M Peeters and P M Koenraad and J H Wolter},
   issue = {10},
   journal = {J Appl Phys},
   keywords = {inversion-layers
impurity scattering
mobility
quantum
gaas
subbands
heterojunctions
dependence
gas},
   pages = {5809-5814},
   title = {Intersubband-coupling and screening effects on the electron transport in a quasi-two-dimensional {\delta}-doped semiconductor system},
   volume = {80},
   year = {1996}
}
@article{Haldane1988,
   author = {F D M Haldane},
   issue = {18},
   journal = {Phys Rev Lett},
   pages = {2015-2018},
   title = {Model for a Quantum Hall-Effect without Landau-Levels - Condensed-Matter Realization of the Parity Anomaly},
   volume = {61},
   year = {1988}
}
@article{Halvorsen2000,
   abstract = {We have used an eight-band model to investigate the electronic structures and to calculate the optical matrix elements of InAs-GaSb broken gap semiconductor heterostructures. The unusual hybridization of the conduction band states in the InAs layers with the valence band states in the GaSb layers has been analyzed in detail. We have studied the dependence of the optical matrix elements on the degree of conduction-valence hybridization, the tuning of the hybridization by varying the width of the GaSb layers and/or InAs layers, and the sensitivity of quantized levels to this tuning. Large spin-orbit splitting in the energy bands has been demonstrated. Our calculation can serve as a theoretical model for infrared lasers based on broken gap quantum well heterostructures.},
   author = {E Halvorsen and Y Galperin and K A Chao},
   issue = {24},
   journal = {Phys Rev B},
   keywords = {negative persistent photoconductivity
alxga1-xsb/inas quantum-wells
electron-hole system
differential resistance
interband
superlattices
transport
inversion
densities
devices},
   pages = {16743-16749},
   title = {Optical transitions in broken gap heterostructures},
   volume = {61},
   year = {2000}
}
@misc{,
   author = {Chihiro Hamaguchi},
   isbn = {9783642033032
3642033032},
   keywords = {Semiconductors.
Electronic books.},
   pages = {1 online resource (xv, 570 pages)},
   title = {Basic semiconductor physics}
}
@book{,
   author = {Chihiro Hamaguchi},
   edition = {Second edition.},
   keywords = {Semiconductors.},
   pages = {pp 287-293},
   publisher = {Springer},
   title = {Basic semiconductor physics}
}
@book{,
   author = {Chihiro Hamaguchi},
   keywords = {Semiconductors.},
   pages = {xii, 434 pages},
   title = {Basic semiconductor physics}
}
@book{Harrison2000,
   author = {P Harrison},
   keywords = {Quantum wells.
Nanowires.
Quantum dots.},
   pages = {xxiv, 456 p.},
   publisher = {John Wiley \& Sons},
   title = {Quantum wells, wires, and dots : theoretical and computational physics},
   year = {2000}
}
@book{Harrison2005,
   author = {P Harrison},
   edition = {2nd},
   keywords = {Quantum wells.
Nanowires.
Quantum dots.},
   pages = {xxvi, 482 p.},
   publisher = {Wiley},
   title = {Quantum wells, wires, and dots : theoretical and computational physics of semiconductor nanostructures},
   year = {2005}
}
@book{,
   author = {P Harrison and Alex Valavanis},
   edition = {Fourth edition.},
   keywords = {Quantum wells.
Nanowires.
Quantum dots.
Electronic books.},
   pages = {1 online resource (xxvi, 598 pages)},
   title = {Quantum wells, wires and dots : theoretical and computational physics of semiconductor nanostructures}
}
@book{Harrison2016,
   author = {P Harrison and Alex Valavanis},
   edition = {Fourth edition.},
   keywords = {Quantum wells.
Nanowires.
Quantum dots.
Electronic books.},
   pages = {1 online resource (xxvi, 598 pages)},
   publisher = {J. Wiley},
   title = {Quantum wells, wires and dots : theoretical and computational physics of semiconductor nanostructures},
   year = {2016}
}
@article{Hasan2010,
   abstract = {Topological insulators are electronic materials that have a bulk band gap like an ordinary insulator but have protected conducting states on their edge or surface. These states are possible due to the combination of spin-orbit interactions and time-reversal symmetry. The two-dimensional (2D) topological insulator is a quantum spin Hall insulator, which is a close cousin of the integer quantum Hall state. A three-dimensional (3D) topological insulator supports novel spin-polarized 2D Dirac fermions on its surface. In this Colloquium the theoretical foundation for topological insulators and superconductors is reviewed and recent experiments are described in which the signatures of topological insulators have been observed. Transport experiments on HgTe/CdTe quantum wells are described that demonstrate the existence of the edge states predicted for the quantum spin Hall insulator. Experiments on Bi1-xSbx, Bi2Se3, Bi2Te3, and Sb2Te3 are then discussed that establish these materials as 3D topological insulators and directly probe the topology of their surface states. Exotic states are described that can occur at the surface of a 3D topological insulator due to an induced energy gap. A magnetic gap leads to a novel quantum Hall state that gives rise to a topological magnetoelectric effect. A superconducting energy gap leads to a state that supports Majorana fermions and may provide a new venue for realizing proposals for topological quantum computation. Prospects for observing these exotic states are also discussed, as well as other potential device applications of topological insulators.},
   author = {M Z Hasan and C L Kane},
   issue = {4},
   journal = {Rev Mod Phys},
   keywords = {quantized hall conductance
hgte quantum-wells
single dirac cone
zero modes
electronic-properties
fractional charge
interface states
surface-states
spin
phase},
   pages = {3045-3067},
   title = {Colloquium: Topological insulators},
   volume = {82},
   year = {2010}
}
@article{Hassan2017,
   abstract = {In this paper, we demonstrate why cubic Rashba spin splitting is observed within inverted doped strained germanium (sGe) hetrostructures. Magnetotransport measurements showed beating within the SdH oscillation, with fast Fourier analysis revealing cubic Rashba spin splitting to be present. A cubic Rashba coefficient of beta = 7.97 x 10(-29) eVm(3) and a spin-splitting energy of Delta = 1.17 meV were determined. The source of the cubic Rashba spin splitting was identified from a combination of ultra low energy secondary ion mass spectrometry analysis and subsequent band structure modelling using Nextnano(3). Ultra-low energy secondary ion mass spectrometry revealed an unintentional, highly B doped near surface region accounted for structure inversion asymmetry, whereas subsequent band structure modelling using Nextnano(3) demonstrates how this asymmetric B doping generates structural inversion asymmetry within the sGe QW structure and cubic Rashba spin splitting realized. Published by AIP Publishing.},
   author = {A H A Hassan and R J H Morris and O A Mironov and S Gabani and A Dobbie and D R Leadley},
   issue = {4},
   journal = {Appl Phys Lett},
   keywords = {quantum-wells
subband
systems
ge},
   pages = {42405},
   title = {An origin behind Rashba spin splitting within inverted doped sGe heterostructures},
   volume = {110},
   year = {2017}
}
@article{Hatzakis1980,
   author = {M Hatzakis and B J Canavello and J M Shaw},
   issue = {4},
   journal = {Ibm J Res Dev},
   pages = {452-460},
   title = {Single-Step Optical Lift-Off Process},
   volume = {24},
   year = {1980}
}
@article{Haugan2012,
   abstract = {We explore the optimum growth space for a 47.0 angstrom InAs/21.5 angstrom Ga0.75In0.25Sb superlattices (SLs) designed for the maximum Auger suppression for a very long wavelength infrared gap. Our growth process produces a consistent gap of 50 +/- 5 meV. However, SL quality is sensitive to the growth temperature (T-g). For the SLs grown at 390-470 degrees C, a photoresponse signal gradually increases as Tg increases from 400 to 440 degrees C. Outside this temperature window, the SL quality deteriorates very rapidly. All SLs were n-type with mobility of similar to 10 000 V/cm(2) and 300 K recombination lifetime of similar to 70 ns for an optimized SL. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4764015]},
   author = {H J Haugan and G J Brown and S Elhamri and W C Mitchel and K Mahalingam and M Kim and G T Noe and N E Ogden and J Kono},
   issue = {17},
   journal = {Appl Phys Lett},
   keywords = {photovoltaic detectors
mu-m
photodiodes
cutoff},
   title = {Impact of growth temperature on InAs/GaInSb strained layer superlattices for very long wavelength infrared detection},
   volume = {101},
   year = {2012}
}
@article{Haugan2015,
   abstract = {In order to develop ternary antimonide-based superlattice (SL) materials for very long wavelength infrared (VLWIR) detection, systematic growth optimization studies were performed to produce high quality ternary materials. For the studies, a SL structure of 47.0 angstrom InAs/21.5 angstrom Ga0.75In0.25Sb was selected to create a very narrow band gap. Results indicate that an epitaxial process developed can produce a precisely controlled band gap around 50 meV, but the material quality of grown SL layers is particularly sensitive to growth defects formed during the growth process. Since Group III antisites and strain-induced dislocations are the dominant structural defects responsible for the low radiative efficiencies, our optimization strategies to eliminate these defects have focused on stabilizing III/V incorporation during surface reconstruction by manipulating the growth surface temperature and balancing the residual strain of the SLs by adjusting the As/Sb flux ratio. The optimized ternary SL materials exhibited an overall strong photoresponse over a wide wavelength range up to similar to 15 mu m that is important for developing VLWIR detectors. A quantitative analysis of the lattice strain, performed at the atomic scale by aberration corrected transmission electron microscopy, provided valuable information about the strain distribution at the interfaces that was important for optimizing the strain balancing process during SL layer growth. (C) 2014 Elsevier B.V. All rights reserved.},
   author = {H J Haugan and G J Brown and K Mahalingam and L Grazulis},
   journal = {Infrared Phys Techn},
   keywords = {superlattices
molecular beam epitaxy
infrared detector
antimonides},
   pages = {99-102},
   title = {Growth optimization studies to develop InAs/GaInSb superlattice materials for very long wavelength infrared detection},
   volume = {70},
   year = {2015}
}
@article{Haugan2014,
   abstract = {The authors report growth studies to develop an InAs/GaInSb superlattice (SL) material for very long wavelength infrared detection. They select a SL structure of 47.0 angstrom InAs/21.5 angstrom Ga0.75In0.25Sb that is designed for the greatest possible detectivity, and tune growth conditions to achieve the best quality ternary material. Since the material quality of grown layers is particularly sensitive to extrinsic defects such as nonradiative recombination centers generated during the growth process, the authors investigate the effect of the growth temperature (T-g) on the spectral photoresponse (PR) and carrier recombination lifetime using photoconductivity and time-resolved differential reflectivity measurements. Results indicate that a molecular beam epitaxy growth process the authors developed produces a consistent energy gap around 50 meV, determined from the PR spectra, but the intensity of the spectra is sensitive to T-g. For SLs grown at T-g between 390 and 470 degrees C, the PR signal intensity gradually increases as T-g increases from 400 to 440 degrees C, reaching a maximum at 440 degrees C. Outside this growth window, the SL quality deteriorates very rapidly. However, the carrier recombination lifetime measured at 300 K was not sensitive to T-g. Although the SL sample grown at 430 degrees C produced the longest lifetime of 84 ns, the average 300 K lifetime value remained around 74 ns. (C) 2014 American Vacuum Society.},
   author = {H J Haugan and G J Brown and K Mahalingam and L Grazulis and G T Noe and N E Ogden and J Kono},
   issue = {2},
   journal = {Journal of Vacuum Science and Technology B},
   keywords = {photovoltaic detectors
mu-m
heterostructures
photodiodes
cutoff},
   title = {Optimum growth window for InAs/GaInSb superlattice materials tailored for very long wavelength infrared detection},
   volume = {32},
   year = {2014}
}
@article{Haugan2016,
   abstract = {Significantly improved carrier lifetimes in very-long wave infrared InAs/GaInSb superlattice (SL) absorbers are demonstrated by using time-resolved microwave reflectance (TMR) measurements. A nominal 47.0 angstrom InAs/21.5 angstrom Ga0.75In0.25Sb SL structure that produces an approximately 25 mu m response at 10 K has a minority carrier lifetime of 140 +/- 20 ns at 18 K, which is markedly long for SL absorber with such a narrow bandgap. This improvement is attributed to the strain-engineered ternary design. Such SL employs a shorter period with reduced gallium in order to achieve good optical absorption and epitaxial advantages, which ultimately leads to the improvements in the minority carrier lifetime by reducing Shockley-Read-Hall (SRH) defects. By analyzing the temperature-dependence of TMR decay data, the recombination mechanisms and trap states that currently limit the performance of this SL absorber have been identified. The results show a general decrease in the long-decay lifetime component, which is dominated by the SRH recombination at temperature below similar to 30 K, and by Auger recombination at temperatures above similar to 45 K. (C) 2016 American Vacuum Society.},
   author = {H J Haugan and G J Brown and B V Olson and E A Kadlec and J K Kim and E A Shaner},
   issue = {2},
   journal = {Journal of Vacuum Science and Technology B},
   keywords = {ii superlattices
detectors},
   title = {Minority carrier lifetimes in very long-wave infrared InAs/GaInSb superlattices},
   volume = {34},
   year = {2016}
}
@article{Haugan2017,
   abstract = {Significantly improved carrier lifetimes in very long-wave infrared (VLWIR) InAs/GaInSb superlattice (SL) absorbers are demonstrated using time-resolved microwave reflectance (TMR) measurements. A nominal 47.0 angstrom InAs/21.5 angstrom Ga0.75In0.25Sb SL structure that produces an similar to 25 mu m response at 10 K has a minority carrier lifetime of 140 +/- 20 ns at 18 K, which is an order-of-magnitude improvement compared with previously reported lifetime values for other VLWIR detector absorbers. This improvement is attributed to the strain-engineered ternary SL design, which offers a variety of epitaxial advantages and ultimately leads to the improvements in the minority carrier lifetime by mitigating defect-mediated Shockley-Read-Hall (SRH) recombination centers. By analyzing the temperature dependence of TMR decay data, the recombination mechanisms and trap states that currently limit the performance of this SL absorber were identified. The results show a general decrease in the long-decay lifetime component, which is dominated by SRH recombination at temperatures below similar to 30 K and by Auger recombination at temperatures above similar to 45 K. Since the strain-balanced ternary SL design offers a reasonably good absorption coefficient and many epitaxial advantages during growth, this VLWIR SL material system should be considered as a competitive candidate for VLWIR photodetector technology. (C) 2017 Society of Photo-Optical Instrumentation Engineers (SPIE)},
   author = {H J Haugan and B V Olson and G J Brown and E A Kadlec and J K Kim and E A Shaner},
   issue = {9},
   journal = {Opt Eng},
   keywords = {inas/gainsb superlattices
infrared detectors
carrier lifetimes
time-resolved microwave reflectance
molecular beam epitaxy
detectors
growth
gasb},
   title = {Significantly enhanced carrier lifetimes of very long-wave infrared absorbers based on strained-layer InAs/GaInSb superlattices},
   volume = {56},
   year = {2017}
}
@article{Heisz1996,
   abstract = {We have calculated the resistivity of a GaAs/AlxGa1-xAs heterojunction in the presence of both an in-plane magnetic field and a weak perpendicular component using a semiclassical Boltzmann transport theory. These calculations take into account fully the distortion of the Fermi contour which is induced by the parallel magnetic field. The scattering of electrons is assumed to be due to remote ionized impurities. A positive magnetoresistance is found as a function of the perpendicular component, in good qualitative agreement with experimental observations. The main source of this effect is the strong variation of the electronic scattering rate around the Fermi contour which is associated with the variation in the mean distance of the electronic states from the remote impurities. The magnitude of the positive magnetoresistance is strongly correlated with the residual acceptor impurity density in the GaAs layer. The carrier lifetime anisotropy also leads to an observable anisotropy in the resistivity with respect to the angle between the current and the direction of the in-plane magnetic field.},
   author = {J M Heisz and E Zaremba},
   issue = {20},
   journal = {Phys Rev B},
   keywords = {heterostructures},
   pages = {13594-13604},
   title = {Transverse magnetoresistance of GaAs/Al_xGa_1-xAs heterojunctions in the presence of parallel magnetic fields},
   volume = {53},
   year = {1996}
}
@article{Hetsch2009,
   abstract = {The influence of sweep on the general structure of short separation bubbles in strictly laminar flow fields on swept infinite geometries is investigated by theoretical analysis and direct numerical simulations (DNS). In this situation the 'independence principle' of the Navier-Stokes equations for incompressible flow enforces a unique topology for the mean flow, which includes the much better understood unswept separation bubbles as a special case: swept laminar separation bubbles form leading edge parallel streamtubes with a spanwise outflow and a helical motion inside directed parallel to the separation line. If chordwise inflow conditions are kept constant, their cross-sections stay independent of a rising sweep angle, as the spanwise velocity field is then merely superimposed over the unchanged flow of the corresponding unswept case. Their mean flow field follows strict scaling rules that may be derived analytically from the generic 45 degrees-solution, as confirmed by DNS-results for a series of pressure-induced separation bubbles subjected to a systematic variation of the sweep angle between 0 degrees and 6 degrees. (C) 2009 Elsevier Masson SAS. All rights reserved.},
   author = {T Hetsch and U Rist},
   issue = {4},
   journal = {Eur J Mech B-Fluid},
   keywords = {swept laminar separation bubbles
independence principle
scaling laws
topology of separated flows
direct numerical-simulation
navier-stokes equations
rearward-facing step
boundary-layer
heat-transfer
transition
flow
mechanisms},
   pages = {486-493},
   title = {An analysis of the structure of laminar separation bubbles in swept infinite geometries},
   volume = {28},
   year = {2009}
}
@article{Herling2017,
   abstract = {We study the spin-orbit interaction (SOI) in InAs/GaSb and InAs quantum wells. We showthrough temperatureand gate-dependent magnetotransport measurements of weak antilocalization that the dominant spin-orbit relaxation mechanism in our low-mobility heterostructures is Elliott-Yafet and not Dyakonov-Perel in the form of the Rashba or Dresselhaus SOI as previously suggested. We compare our findings with recent work on this material system and show that the SOI length lies within the same range. The SOI length may be controlled using an electrostatic gate, opening up prospects for developing spintronic applications.},
   author = {F Herling and C Morrison and C S Knox and S Zhang and O Newell and M Myronov and E H Linfield and C H Marrows},
   issue = {15},
   journal = {Phys Rev B},
   keywords = {quantum-wells
inversion-layers
inas
hybridization
systems
films
gasb
gap},
   title = {Spin-orbit interaction in InAs/GaSb heterostructures quantified by weak antilocalization},
   volume = {95},
   year = {2017}
}
@article{Hikami1980,
   author = {S Hikami and A I Larkin and Y Nagaoka},
   issue = {2},
   journal = {Prog Theor Phys},
   pages = {707-710},
   title = {Spin-Orbit Interaction and Magnetoresistance in the 2 Dimensional Random System},
   volume = {63},
   year = {1980}
}
@article{Hirsch1999,
   abstract = {It is proposed that when a charge current circulates in a paramagnetic metal a transverse spin imbalance will be generated, giving rise to a "spin Hall voltage." Similarly, it is proposed that when a spin current circulates a transverse charge imbalance will be generated, giving rise to a Hall voltage, in the absence of charge current and magnetic field. Based on these principles we propose an experiment to generate and detect a spin current in a paramagnetic metal.},
   author = {J E Hirsch},
   issue = {9},
   journal = {Phys Rev Lett},
   keywords = {2-dimensional electron-systems
transport
charge},
   pages = {1834-1837},
   title = {Spin Hall effect},
   volume = {83},
   year = {1999}
}
@article{Hirsch2010,
   abstract = {The observation of the H-mode and ELMs in helical devices confirms the generic character of these phenomena in toroidal confinement. Particularities are the strong impact of the magnetic edge configuration on transition and ELM phenomenology and the existence of a mean E x B flow shear already predefined by the condition given from the neoclassical fluxes. The observations indicate that the classical H-mode as a bifurcation phenomenon possibly associated with dynamic sheared flows is biased by these equilibrium mean shear flow conditions of the 3D plasma edge. Besides this classical H-mode other Edge Transport Barriers can be realized which are related to the development a mean shear flow on a transport timescale. (C) 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim},
   author = {M Hirsch},
   issue = {6-7},
   journal = {Contrib Plasm Phys},
   keywords = {h-mode
helical devices
flow shear
zonal flows
mode
confinement},
   pages = {487-492},
   title = {Overview of L-H Transition Experiments in Helical Devices},
   volume = {50},
   year = {2010}
}
@article{Hu2012,
   abstract = {Two- dimensional topological insulators (2D TIs) have been proposed as platforms for many intriguing applications, ranging from spintronics to topological quantum information processing. Realizing this potential will likely be facilitated by the discovery of new, easily manufactured materials in this class. With this goal in mind, we introduce a new framework for engineering a 2D TI by hybridizing graphene with impurity bands arising from heavy adatoms possessing partially filled d shells, in particular, osmium and iridium. First-principles calculations predict that the gaps generated by this means exceed 0.2 eV over a broad range of adatom coverage; moreover, tuning of the Fermi level is not required to enter the TI state. The mechanism at work is expected to be rather general and may open the door to designing new TI phases in many materials. DOI: 10.1103/PhysRevLett.109.266801},
   author = {J Hu and J Alicea and R Q Wu and M Franz},
   issue = {26},
   journal = {Phys Rev Lett},
   keywords = {total-energy calculations
hgte quantum-wells
wave basis-set
state
transition},
   title = {Giant Topological Insulator Gap in Graphene with 5d Adatoms},
   volume = {109},
   year = {2012}
}
@article{Hwang1993,
   abstract = {In a low-mobility InxGa1-xAs/InP heterostructure, we find that the quantized Hall resistance plateau, rho(xy) = h/ie2 with i = 3, starts developing only when T is below 50 mK. For higher T, the plateau and the associated minimum in the diagonal resistivity p. can be made to appear by tilting the sample with respect to the B field. We have studied the T dependence of the p. minimum and deduced the thermal-activation energy (A). We find that A is 67 times smaller than the Landau-level broadening deduced from the electron mobility. This result implies that there is no gap in the density of states and that, for T > 50 mK, the Landau level is spin degenerate. In this higher T range, we observe a T-0.21 power law for the maximum value of drho(xy)/dB between the i = 2 and 4 plateaus, and T-0.42 for the minimum value of d2prho(xx)/dB2. These exponents are a factor 2 smaller than those for spin-polarized levels.},
   author = {S W Hwang and H P Wei and L W Engel and D C Tsui and A M M Pruisken},
   issue = {15},
   journal = {Phys Rev B},
   keywords = {2 dimensions
magnetic-fields
localization},
   pages = {11416-11419},
   title = {Scaling in Spin-Degenerate Landau-Levels in the Integer Quantum Hall-Effect},
   volume = {48},
   year = {1993}
}
@article{Isihara1986,
   author = {A Isihara and L Smrcka},
   issue = {34},
   journal = {J Phys C Solid State},
   pages = {6777-6789},
   title = {Density and Magnetic-Field Dependences of the Conductivity of Two-Dimensional Electron-Systems},
   volume = {19},
   year = {1986}
}
@article{Jacob2010,
   abstract = {We give an overview of the generation of spin-polarized currents in all-semiconductor devices by utilizing the intrinsic spin-Hall effect. Two-staged cascades of Y-shaped three-terminal junctions of narrow quantum wires fabricated from In As heterostructures with strong Rashba spin orbit interaction allow all-electrical generation and detection of spin-polarized currents. We compare our low-temperature transport measurements to numerical simulations and find in both highly spin-polarized currents in the case of transport in the lowest one-dimensional subband.},
   author = {J Jacob and T Matsuyama and G Meier and U Merkt},
   journal = {Nanosci Technol},
   keywords = {quantized ballistic resistance
quantum point contacts
electron-gas
polarization
wells
heterostructures
semiconductors
ferromagnets
constriction
conductance},
   pages = {303-326},
   title = {InAs Spin Filters Based on the Spin-Hall Effect},
   year = {2010}
}
@article{Jalonen2000,
   abstract = {Miniaturization in electronics means finer lines and smaller vias in substrate technology. Very fine lines on the substrate are difficult to produce by conventional means. Thick copper layers are difficult to etch and the accuracy of conventional dry dim photoresist is not necessarily sufficient. Environmental issues force us to reduce pollution in the environment. One very promising means of achieving fine lines is the etching of sputtered thin films on the substrate and growing the copper with an additive method on the tiny lines. It has been shown that using dry film photoresist is not suitable for very narrow lines. Spinning the photo resist is an alternative, but in the test, its adhesion was not good enough. Most narrow resist lines were washed away in the development stage. To meet requirements for accuracy, the best method seemed to be the electrodeposited method, in which a very thin, even, homogenous photoresist layer can be generated. This fine layer is developed easily, thus allowing the transfer of fine line images to the substrate. To get good accuracy on the metal lines, the core material beneath the sputtered metal layer must be smooth enough. Apparently best accuracy can be achieved only with the smoothest surface. The differences between the original and only slightly brushed surfaces are not so obvious.},
   author = {P Jalonen and A Tuominen},
   journal = {Proceedings of International Symposium on Electronic Materials and Packaging},
   pages = {156-159},
   title = {The effect of core material surface roughness on line accuracy using electrodeposited photoresist},
   year = {2000}
}
@article{Jeckelmann2001,
   abstract = {The quantum Hall effect (QHE) provides an invariant reference for resistance linked to natural constants. It is used worldwide to maintain and compare the unit of resistance. The reproducibility reached today is almost two orders of magnitude better than the uncertainty of the determination of the ohm in the international system of units SI.
In this article, mainly the aspects of the QHE relevant for its metrological application are reviewed. After a short introduction of the theoretical models describing the integer QHE, the properties of the devices used in metrology and the measurement techniques are described. A detailed summary is given on the measurements carried out to demonstrate the universality of the quantized Hall resistance and to assess all the effects leading to deviations of the Hall resistance from the quantized value. In addition, the present and future role of the QHE in the SI and the field of natural constants is discussed.},
   author = {B Jeckelmann and B Jeanneret},
   issue = {12},
   journal = {Rep Prog Phys},
   keywords = {cryogenic current comparator
fine-structure constant
strong magnetic-fields
high-precision measurements
two-dimensional systems
finite-size corrections
small tunnel-junctions
quasi-particle charge
dc current resolution
landau-level tails},
   pages = {1603-1655},
   title = {The quantum Hall effect as an electrical resistance standard},
   volume = {64},
   year = {2001}
}
@article{Jeckelmann2003,
   abstract = {The quantum Hall effect (QHE) provides an invariant reference for resistance linked to natural constants. It is used worldwide to maintain and compare the unit of resistance. The reproducibility reached today is almost two orders of magitude better than the uncertainty of the determination of the ohm in the International System of Units. This article is a summary of a recently published review article which focuses mainly on the aspects of the QHE relevant for its metrological application.},
   author = {B Jeckelmann and B Jeanneret},
   issue = {8},
   journal = {Meas Sci Technol},
   keywords = {resistance
international system of units
quantum standards
quantum hall effect
resistance bridges
fine-structure constant
josephson potentiometer
ratio bridge
si ohm
silicon
improvements
realization
transport
capacitor
accuracy},
   pages = {1229-1236},
   title = {The quantum Hall effect as an electrical resistance standard},
   volume = {14},
   year = {2003}
}
@article{Jeckelmann2005,
   abstract = {The quantum Hall effect (QHE) provides an invariant reference for resistance linked to natural constants. It is used worldwide to maintain and compare the unit of resistance. The reproducibility reached today is almost two orders of magnitude better than the uncertainty of the determination of the ohm in the International System of Units SI.
In this article, mainly the aspects of the QHE relevant for its metrological application are reviewed. After a short introduction of the theoretical models describing the integer QHE, the properties of the devices used in metrology and the measurement techniques are described. A detailed summary is given on the measurements carried out to demonstrate the universality of the quantized Hall resistance and to assess all the effects leading to deviations of the Hall resistance from the quantized value. In addition, the present and future role of the QHE in the SI and the field of natural constants is discussed.},
   author = {B Jeckelmann and B Jeanneret},
   journal = {Prog Math Phys},
   keywords = {cryogenic current comparator
fine-structure constant
strong magnetic-fields
high-precision measurements
finite-size corrections
small tunnel-junctions
quasi-particle charge
dc current resolution
landau-level tails
quantized hall},
   pages = {55-131},
   title = {The quantum Hall effect as an electrical resistance standard},
   volume = {45},
   year = {2005}
}
@article{Jerome1967,
   author = {D Jerome and T M Rice and W Kohn},
   issue = {2},
   journal = {Phys Rev},
   pages = {462-475},
   title = {Excitonic Insulator},
   volume = {158},
   year = {1967}
}
@article{Johnson2000,
   abstract = {The investigation of the InAs / Ga1-x In-x Sb strained layer superlattice (SLS) has been largely motivated by the promise of overcoming limitations of current mature high-performance infrared detectors. such as those using HgCdTe and extrinsic silicon, it also offers fundamentally superior performance over other newly emerging III-V bandgap-engineered materials such as QWIPs. The inherent properties of the InAs/GalnSb SLS have identified it as an attractive alternative for niche VLWIR applications requiring high performance under low backgrounds at operating temperatures > 40K. It. this material system proves to meet the stringent demands of VLWIR applications, it will most certainly play a significant role as an alternative material for photovoltaic focal plane arrays operating in the LWIR and MWIR regimes as well. This paper is an overview of SLS technology development. and focuses on critical development needs as seen from the perspective of the infrared detector industry.},
   author = {J L Johnson},
   journal = {Photodetectors: Materials and Devices V},
   keywords = {infrared detectors
superlattice
focal plane array
inas/gainsb
strained layer superlattice
ii superlattices
photodiodes
gasb
photodetectors
performance},
   pages = {118-132},
   title = {The InAs/GaInSb strained layer superlattice as an infrared detector material: An overview},
   volume = {3948},
   year = {2000}
}
@article{Johnson2014,
   abstract = {Atomic layer deposition (ALD) is a vapor phase technique capable of producing thin films of a variety of materials. Based on sequential, self-limiting reactions, ALD offers exceptional conformality on high-aspect ratio structures, thickness control at the Angstrom level, and tunable film composition. With these advantages, ALD has emerged as a powerful tool for many industrial and research applications. In this review, we provide a brief introduction to ALD and highlight select applications, including Cu(In,Ga)Se-2 solar cell devices, high-k transistors, and solid oxide fuel cells. These examples are chosen to illustrate the variety of technologies that are impacted by ALD, the range of materials that ALD can deposit - from metal oxides such as Zn1-xSnxOy, ZrO2, Y2O3, to noble metals such as Pt - and the way in which the unique features of ALD can enable new levels of performance and deeper fundamental understanding to be achieved.},
   author = {R W Johnson and A Hultqvist and S F Bent},
   issue = {5},
   journal = {Mater Today},
   keywords = {oxide fuel-cells
yttria-stabilized zirconia
thin-film photovoltaics
sensitized solar-cells
buffer layers
ternary oxides
metal
ald
transistors
chemistry},
   pages = {236-246},
   title = {A brief review of atomic layer deposition: from fundamentals to applications},
   volume = {17},
   year = {2014}
}
@article{Kainaris2014,
   abstract = {A quantum spin Hall insulator is a two-dimensional state of matter consisting of an insulating bulk and one-dimensional helical edge states. While these edge states are topologically protected against elastic backscattering in the presence of disorder, interaction-induced inelastic terms may yield a finite conductivity. By using a kinetic equation approach, we find the backscattering rate tau(-1) and the semiclassical conductivity in the regimes of high (omega >> tau(-1)) and low (omega << tau(-1)) frequency. By comparing the two limits, we find that the parametric dependence of conductivity is described by the Drude formula for the case of a disordered edge. On the other hand, in the clean case where the resistance originates from umklapp interactions, the conductivity takes a non-Drude form with a parametric suppression of scattering in the dc limit as compared to the ac case. This behavior is due to the peculiarity of umklapp scattering processes involving necessarily the state at the "Dirac point." In order to take into account Luttinger liquid effects, we complement the kinetic equation analysis by treating interactions exactly in bosonization and calculating conductivity using the Kubo formula. In this way, we obtain the frequency and temperature dependence of conductivity over a wide range of parameters. We find the temperature and frequency dependence of the transport scattering time in a disordered system as tau similar to [max (omega, T)](-2K-2), for K > 2/3 and tau similar to [max (omega, T)](-8K+2) for K < 2/3.},
   author = {N Kainaris and I V Gornyi and S T Carr and A D Mirlin},
   issue = {7},
   journal = {Phys Rev B},
   keywords = {quantized hall conductance
hgte quantum-wells
topological insulators
state},
   title = {Conductivity of a generic helical liquid},
   volume = {90},
   year = {2014}
}
@article{Kane2005,
   abstract = {We study the effects of spin orbit interactions on the low energy electronic structure of a single plane of graphene. We find that in an experimentally accessible low temperature regime the symmetry allowed spin orbit potential converts graphene from an ideal two-dimensional semimetallic state to a quantum spin Hall insulator. This novel electronic state of matter is gapped in the bulk and supports the transport of spin and charge in gapless edge states that propagate at the sample boundaries. The edge states are nonchiral, but they are insensitive to disorder because their directionality is correlated with spin. The spin and charge conductances in these edge states are calculated and the effects of temperature, chemical potential, Rashba coupling, disorder, and symmetry breaking fields are discussed.},
   author = {C L Kane and E J Mele},
   issue = {22},
   journal = {Phys. Rev. Lett.},
   keywords = {graphite},
   pages = {226801},
   title = {Quantum spin Hall effect in graphene},
   volume = {95},
   year = {2005}
}
@article{Kato2004,
   abstract = {Electrically induced electron-spin polarization near the edges of a semiconductor channel was detected and imaged with the use of Kerr rotation microscopy. The polarization is out-of-plane and has opposite sign for the two edges, consistent with the predictions of the spin Hall effect. Measurements of unstrained gallium arsenide and strained indium gallium arsenide samples reveal that strain modifies spin accumulation at zero magnetic field. A weak dependence on crystal orientation for the strained samples suggests that the mechanism is the extrinsic spin Hall effect.},
   author = {Y K Kato and R C Myers and A C Gossard and D D Awschalom},
   issue = {5703},
   journal = {Science},
   pages = {1910-1913},
   title = {Observation of the spin Hall effect in semiconductors},
   volume = {306},
   year = {2004}
}
@article{Karalic2016,
   abstract = {Transport measurements are performed on InAs/GaSb double quantum wells at zero and finite magnetic fields applied parallel and perpendicular to the quantum wells. We investigate a sample in the inverted regime where electrons and holes coexist, and compare it with another sample in the noninverted semiconducting regime. The activated behavior in conjunction with a strong suppression of the resistance peak at the charge neutrality point in a parallelmagnetic field attest to the topological hybridization gap between electron and hole bands in the inverted sample. We observe an unconventional Landau level spectrum with energy gaps modulated by the magnetic field applied perpendicular to the quantum wells. This is caused by a strong spin-orbit interaction provided jointly by the InAs and the GaSb quantum wells.},
   author = {M Karalic and S Mueller and C Mittag and K Pakrouski and Q S Wu and A A Soluyanov and M Troyer and T Tschirky and W Wegscheider and K Ensslin and T Ihn},
   issue = {24},
   journal = {Phys Rev B},
   keywords = {electron
hybridization
resonance
field},
   pages = {241402},
   title = {Experimental signatures of the inverted phase in InAs/GaSb coupled quantum wells},
   volume = {94},
   year = {2016}
}
@book{Kent1993,
   author = {Anthony Kent},
   keywords = {Low temperature research.},
   pages = {1-216},
   publisher = {Macmillan},
   title = {Experimental low temperature physics},
   year = {1993}
}
@book{Kiethley2012,
   author = {George Kiethley},
   publisher = {Plain View Press},
   title = {Ring of fire},
   year = {2012}
}
@article{Kim2003,
   abstract = {Type-II superlattices (SLs) based on InAs/GaInSb material systems have been theoretically investigated and optimized to achieve large valence band splitting and thin constituent layers, which are desirable for high detectivity and large absorption coefficient for the long-wavelength infrared (LWIR) and very long-wavelength infrared (VLWIR) detection covering the waveband from 8 to 14 mum and longer. Two approaches have been employed to optimize the SL: the first approach is to increase the InSb mole fraction in GaInSb alloy, keeping the balance between the compression and tension in the SL, and the second approach is to increase the SL thickness ratio, allowing small misfit in the SL. In the first approach, the valence band splitting was found to increase with increasing InSb composition and reached a maximum at 25% of InSb composition for 9 mum and at 30% of InSb composition for 11, 13, 15, 17, and 19 mum peak wavelength, respectively. When the thickness ratio is increased with fixed InSb composition, the valence band splitting has its maximum around a thickness ratio of 2-3, but the advantage of increasing the thickness ratio is obtained only for SL with less than 15% of InSb composition. It was also found in the first approach that higher InSb composition in GaInSb alloy was very efficient in reducing the total thickness of one period of SL up to 35% of InSb mole fraction. In the second approach, the minimum thickness of SL is obtained at the point where the valence band splitting is maximized. However, since the second approach is useful only for InSb composition less than 15%, the reduction of total thickness of SL is less effective than the first approach. Consequently, we can design high performance type-II SL IR detectors by both approaches for LWIR and VLWIR applications. (C) 2002 Elsevier Science B.V. All rights reserved.},
   author = {S H Kim and S S Li},
   issue = {2},
   journal = {Physica E-Low-Dimensional Systems and Nanostructures},
   keywords = {type-ii superlattice (sl)
inas/gainsb
ir detector
lwir
vlwir
photodiodes},
   pages = {199-208},
   title = {Theoretical investigation of InAs/GaInSb type-II superlattice infrared detectors for long wavelength and very long wavelength infrared applications},
   volume = {16},
   year = {2003}
}
@article{Kishore2012,
   abstract = {The electronic and optical properties of InAs/GaSb core-shell nanowires are investigated within the effective mass k . p approach. These systems have a broken band gap, which results in spatially separated confinement of electrons and holes. We investigated these structures for different sizes of the InAs and GaSb core and shell radius. We found that for certain configurations, the conduction band states penetrate into the valence band states resulting in a negative band gap (E-g < 0), which leads to a conduction band ground state that lies below the valence band ground state at the Gamma point. For certain core-shell wires, only one conduction band state penetrates into the valence band and in this case, a minigap Delta opens up away from the Gamma point and as a consequence the electronic properties of the nanowire now depend on both E-g and Delta values.},
   author = {V V R Kishore and B Partoens and F M Peeters},
   issue = {16},
   journal = {Phys Rev B},
   keywords = {wavelength infrared range
gasb super-lattices
hgte quantum-wells
superlattice photodiodes
semimetallic superlattices
optical-transitions
inas
heterostructures
growth
gap},
   title = {Electronic structure of InAs/GaSb core-shell nanowires},
   volume = {86},
   year = {2012}
}
@article{Kiss2016,
   abstract = {We generalize the Elliott-Yafet (EY) theory of spin relaxation in metals with inversion symmetry for the case of large spin-orbit coupling (SOC). The EY theory treats the SOC to the lowest order but this approach breaks down for metals of heavy elements (such as e.g. caesium or gold), where the SOC energy is comparable to the relevant band-band separation energies. The generalized theory is presented for a four-band model system without band dispersion, where analytic formulae are attainable for arbitrary SOC for the relation between the momentum-and spin-relaxation rates. As an extended description, we also consider an empirical pseudopotential approximation where SOC is deduced from the band potential (apart from an empirical scaling constant) and the spin-relaxation rate can be obtained numerically. Both approaches recover the usual EY theory for weak SOC and give that the spin-relaxation rate approaches the momentum-relaxation rate in the limit of strong SOC. We argue that this limit is realized in gold by analyzing spin relaxation data. A calculation of the g-factor shows that the empirical Elliott-relation, which links the g-factor and spin-relaxation rate, is retained even for strong SOC.},
   author = {A Kiss and L Szolnoki and F Simon},
   journal = {Sci Rep-Uk},
   keywords = {conduction electrons
metals
gold
semiconductors
resonance
silver},
   pages = {22706},
   title = {The Elliott-Yafet theory of spin relaxation generalized for large spin-orbit coupling},
   volume = {6},
   year = {2016}
}
@article{Kitchin2002,
   abstract = {A large scale investigation into the effects of alloy layer disorder on emission in antimonide-based superlattices is reported. The potential utility of these systems in infrared (IR) optoelectronic technologies is reviewed and issues inhibiting their realization identified. The Ga0.7In0.3Sb alloy layer is modeled using both the conventional virtual crystal approximation and models which describe microscopic disorder, clustering, and atomistic relaxation. The structures have recently been fabricated for IR laser applications and we investigate the influence of the alloy description on the emission line shapes. For each superlattice we find that the emission linewidth and peak height is very sensitive to the microscopic details of the alloy potential. Comparing the various superlattice systems, which differ regarding the InAs layer widths, we find that their linewidth values (eV) are each of the same order of magnitude for a given population of excited carriers. While values show a strong dependence on the period, reflecting large differences in the interband transition probabilities, the relationship between linewidth and excited carrier population does not show a clear correlation with superlattice period. This article demonstrates quantitative links between microscopic disorder and the optical properties of strained-layer superlattices. (C) 2002 American Vacuum Society.},
   author = {M R Kitchin and M J Shaw and J P Hagon and M Jaros},
   issue = {1},
   journal = {Journal of Vacuum Science and Technology B},
   keywords = {quantum-well lasers
optical-properties
interband cascade
heterostructures
absorption
interfaces
growth},
   pages = {209-215},
   title = {Alloy layer disorder in strained-layer InAs/GaInSb/AlSb superlattices with infrared laser applications},
   volume = {20},
   year = {2002}
}
@book{Kittel1976,
   author = {Charles Kittel},
   edition = {7th},
   keywords = {Solid state physics.},
   pages = {154-176},
   publisher = {Wiley},
   title = {Introduction to solid state physics},
   year = {1976}
}
@book{Kittel1996,
   author = {Charles Kittel},
   edition = {7th},
   keywords = {Solid state physics.},
   pages = {xi, 673 p.},
   publisher = {Wiley},
   title = {Introduction to solid state physics},
   year = {1996}
}
@article{Kleinert2008,
   abstract = {Based on rigorous quantum-kinetic equations for the spin-density matrix, spin-charge coupled drift-diffusion equations are derived for a strongly confined two-dimensional hole gas. An electric field leads to a coupling between the spin and charge degrees of freedom. For weak spin-orbit interaction, this coupling gives rise to the intrinsic spin-Hall effect that occurs in the diffusive regime. There exists a threshold value of the spin-orbit coupling constant that separates spin diffusion from ballistic spin transport. In the latter regime, undamped spin-coherent oscillations are observed. Their relationship to the zitterbewegung is discussed. The analytic results are compared with an exact microscopic approach valid in the ballistic regime. (c) 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.},
   author = {P Kleinert and V V Bryksin},
   issue = {1},
   journal = {Phys Status Solidi C},
   pages = {310-313},
   title = {Spin-Hall effect and spin coherent waves in semiconductors with Rashba spin-orbit interaction},
   volume = {5},
   year = {2008}
}
@article{Klipstein2015,
   author = {P C Klipstein},
   issue = {3},
   journal = {Phys Rev B},
   title = {Publisher's Note: Structure of the quantum spin Hall states in HgTe/CdTe and InAs/GaSb/AlSb quantum wells (vol 91, 035310, 2015)},
   volume = {91},
   year = {2015}
}
@article{Klipstein2016,
   abstract = {A solution of the 4 x 4 k . p Hamiltonian for the quantum spin Hall (QSH) edge states in ideal semiconductor topological insulator (TI) quantum wells (QWs) was recently demonstrated by the author using standard boundary conditions for the wave function and its derivative, in order to address unphysical behavior associated with open boundary conditions (Klipstein 2015 Phys. Rev. B 91 035310). For HgTe/CdTe QWs which have strong s-p hybridization, there are two non-degenerate solutions in each spin direction with a finite amplitude at the edge, one of which was shown to be spurious. For the case of weakly hybridized InAs/GaSb/AlSb QWs, the solutions near the zone center are degenerate, and the question is now settled of which solution is spurious. The physical solutions for the ideal QW are then used as the basis for a perturbation treatment of the edge state dispersions in realistic QWs, where interface, bulk and structural asymmetries are also present. Interactions are included with more remote states than considered previously, as required for a consistent treatment of the TI bulk states, where a large difference exists in the spin splittings of the conduction and valence band edges. The asymmetry perturbations induce only minor changes to the edge state dispersions, which no longer merge smoothly with the bulk band extrema.},
   author = {P C Klipstein},
   issue = {37},
   journal = {J Phys-Condens Mat},
   keywords = {topological insulator
edge states
kp method
inversion asymmetry
structural asymmetry
quantum spin hall effect
topological insulators
electrons},
   title = {Spurious and realistic solutions for the quantum spin Hall edge states in InAs/GaSb/AlSb quantum wells},
   volume = {28},
   year = {2016}
}
@misc{,
   author = {Ivan Knez},
   institution = {Rice University, 2012.},
   title = {Transport properties of topological phases in broken gap InAs/GaSb based quantum wells}
}
@article{Knez2012,
   abstract = {We review the recent experimental progress towards observing quantum spin Hall effect in inverted InAs/GaSb quantum wells (QWs). Low temperature transport measurements in the hybridization gap show bulk conductivity of a non-trivial origin, while the length and width dependence of conductance in this regime show strong evidence for the existence of helical edge modes proposed by Liu et al. [Phys. Rev. Lett., 2008, 100: 236601]. Surprisingly, edge modes persist in spite of comparable bulk conduction and show only weak dependence on magnetic field. We elucidate that seeming independence of edge on bulk transport comes due to the disparity in Fermi-wave vectors between the bulk and the edge, leading to a total internal reflection of the edge modes.},
   author = {I Knez and R R Du},
   issue = {2},
   journal = {Front Phys-Beijing},
   keywords = {quantum spin hall effect
inas/gasb quantum wells
topological insulators
insulator
hybridization
phase
holes},
   pages = {200-207},
   title = {Quantum spin Hall effect in inverted InAs/GaSb quantum wells},
   volume = {7},
   year = {2012}
}
@article{Knez2010,
   abstract = {We have studied experimentally the low-temperature conductivity of mesoscopic size InAs/GaSb quantum well Hall bar devices in the inverted regime. Using a pair of electrostatic gates we move the Fermi level into the electron-hole hybridization state, observing a mini gap and Van Hove singularity at its edge. Temperature dependence of the conductivity in the gap shows a residual conductivity, which can be consistently explained by the contributions from the free as well as the hybridized carriers in the presence of impurity scattering, as proposed by Naveh and Laikhtman, [Europhys. Lett. 55, 545 (2001)]. Experimental implications for the stability of proposed quantum spin Hall helical edge states will be discussed.},
   author = {I Knez and R R Du and G Sullivan},
   issue = {20},
   journal = {Phys Rev B},
   keywords = {resistance resonance
band-structure
electron
inas
alsb
hybridization
scattering
holes},
   pages = {201301},
   title = {Finite conductivity in mesoscopic Hall bars of inverted InAs/GaSb quantum wells},
   volume = {81},
   year = {2010}
}
@article{Knez2011,
   abstract = {We present an experimental study of low temperature electronic transport in the hybridization gap of inverted InAs/GaSb composite quantum wells. An electrostatic gate is used to push the Fermi level into the gap regime, where the conductance as a function of sample length and width is measured. Our analysis shows strong evidence for the existence of helical edge modes proposed by Liu et al [Phys. Rev. Lett. 100, 236601 (2008)]. Edge modes persist in spite of sizable bulk conduction and show only a weak magnetic field dependence-a direct consequence of a gap opening away from the zone center.},
   author = {I Knez and R R Du and G Sullivan},
   issue = {13},
   journal = {Phys Rev Lett},
   keywords = {hybridization},
   pages = {136603},
   title = {Evidence for Helical Edge Modes in Inverted InAs/GaSb Quantum Wells},
   volume = {107},
   year = {2011}
}
@article{Knez2014,
   abstract = {We observe edge transport in the topologically insulating InAs/GaSb system in the disordered regime. Using asymmetric current paths we show that conduction occurs exclusively along the device edge, exhibiting a large Hall signal at zero magnetic fields, while for symmetric current paths, the conductance between the two mesoscopicly separated probes is quantized to 2e(2)/h. Both quantized and self-averaged transport show resilience to magnetic fields, and are temperature independent for temperatures between 20 mK and 1 K.},
   author = {I Knez and C T Rettner and S H Yang and S S P Parkin and L J Du and R R Du and G Sullivan},
   issue = {2},
   journal = {Phys Rev Lett},
   keywords = {state},
   pages = {26804},
   title = {Observation of Edge Transport in the Disordered Regime of Topologically Insulating InAs/GaSb Quantum Wells},
   volume = {112},
   year = {2014}
}
@article{Knox2018,
   abstract = {The Dresselhaus spin-orbit interaction is expected to perturb the quantum spin Hall phase predicted to arise within InAs/GaSb coupled quantum wells. To gain a greater understanding of this interaction, the spin-orbit coupling in two InAs/GaSb coupled quantum well samples, grown along the [001] axis, was investigated along three different in-plane crystallographic axes. By measuring the crystallographic axis dependence of the Dresselhaus spin-orbit coupling, we can deconvolute this coupling from the spin splitting arising from axis-invariant Rashba spin-orbit coupling. We find that the Dresselhaus parameter is robust against an external gate bias and small changes in growth conditions, with an associated Dresselhaus parameter of (0.20 +/- 0.08)x10(-11) eVm being measured across all samples and top gate bias conditions. In addition, we show that the asymmetries associated with the coupled quantum well structure, leading to Rashba spin-orbit coupling, are likely to play a dominant role in determining the spin-orbit interaction experienced by a quantum spin Hall state as the system is tuned towards charge neutrality.},
   author = {C S Knox and L H Li and M C Rosamond and E H Linfield and C H Marrows},
   issue = {15},
   journal = {Phys Rev B},
   keywords = {relaxation
insulator
electrons
holes
inas},
   pages = {155323},
   title = {Deconvolution of Rashba and Dresselhaus spin-orbit coupling by crystal axis dependent measurements of coupled InAs/GaSb quantum wells},
   volume = {98},
   year = {2018}
}
@article{Knox2017,
   abstract = {InAs/GaSb coupled quantum well heterostructures are important semiconductor systems with applications ranging from spintronics to photonics. Most recently, InAs/GaSb heterostructures have been identified as candidate two-dimensional topological insulators, predicted to exhibit helical edge conduction via fully spin-polarised carriers. We study an InAs/GaSb double quantum well heterostructure with an AlSb barrier to decouple partially the 2D electrons and holes, and find conduction consistent with a 2D hole gas, with an effective mass of 0.235 +/- 0.005 m(0), existing simultaneously with hybridised carriers with an effective mass of 0.070 +/- 0.005 m(0), where m(0) is the bare electron mass.},
   author = {C S Knox and C Morrison and F Herling and D A Ritchie and O Newell and M Myronov and E H Linfield and C H Marrows},
   issue = {10},
   journal = {Semicond Sci Tech},
   keywords = {inas/gasb
effective mass
hybridisation
cyclotron-resonance},
   pages = {104002},
   title = {Partial hybridisation of electron-hole states in an InAs/GaSb double quantum well heterostructure},
   volume = {32},
   year = {2017}
}
@article{Komnik2000,
   abstract = {The temperature and magnetic-field dependences of the resistance of Si/SiGe heterojunctions with hole-type conductivity are investigated. It is shown that the features of these dependences are due to a manifestation of quantum interference effects - weak localization of the mobile charge carriers, and the hole-hole interaction in the two-dimensional electron system. On the basis of an analysis of the quantum interference effects, the temperature dependence of the dephasing time of the wave function of the charge carrier is determined: tau(Phi)=6.6x10(-12)T(-1) s. This dependence tau(Phi)proportional to T-1 must be regarded as a manifestation of hole-hole scattering processes in the two-dimensional electron system. The contribution to the magnetoresistance from the hole-hole interaction in the Cooper channel is extracted, and the corresponding interaction constant lambda(0)(C)approximate to 0.5 is found. (C) 2000 American Institute of Physics. [S1063-777X(00)01208-1].},
   author = {Y F Komnik and V V Andrievskii and I B Berkutov and S S Kryachko and M Myronov and T E Whall},
   issue = {8},
   journal = {Low Temp Phys+},
   keywords = {two-dimensional systems
heterostructures
magnetoresistance
localization
conductivity
oscillations},
   pages = {609-614},
   title = {Quantum effects in hole-type Si/SiGe heterojunctions},
   volume = {26},
   year = {2000}
}
@article{Konig2013,
   abstract = {The discovery of the quantum spin Hall (QSH) state, and topological insulators in general, has sparked strong experimental efforts. Transport studies of the quantum spin Hall state have confirmed the presence of edge states, showed ballistic edge transport in micron-sized samples, and demonstrated the spin polarization of the helical edge states. While these experiments have confirmed the broad theoretical model, the properties of the QSH edge states have not yet been investigated on a local scale. Using scanning gate microscopy to perturb the QSH edge states on a submicron scale, we identify well-localized scattering sites which likely limit the expected nondissipative transport in the helical edge channels. In the micron-sized regions between the scattering sites, the edge states appear to propagate unperturbed, as expected for an ideal QSH system, and are found to be robust against weak induced potential fluctuations. DOI: 10.1103/PhysRevX.3.021003},
   author = {M Konig and M Baenninger and A G F Garcia and N Harjee and B L Pruitt and C Ames and P Leubner and C Brune and H Buhmann and L W Molenkamp and D Goldhaber-Gordon},
   issue = {2},
   journal = {Phys Rev X},
   keywords = {branched flow
nanostructures
transport
charge
wells},
   title = {Spatially Resolved Study of Backscattering in the Quantum Spin Hall State},
   volume = {3},
   year = {2013}
}
@article{Konig2008,
   abstract = {The search for topologically non-trivial states of matter has become an important goal for condensed matter physics. Recently, a new class of topological insulators has been proposed. These topological insulators have an insulating gap in the bulk, but have topologically protected edge states due to the time reversal symmetry. In two dimensions the helical edge states give rise to the quantum spin Hall (QSH) effect, in the absence of any external magnetic field. Here we review a recent theory which predicts that the QSH state can be realized in HgTe/CdTe semiconductor quantum wells (QWs). By varying the thickness of the QW, the band structure changes from a normal to an "inverted" type at a critical thickness d(c). We present an analytical solution of the helical edge states and explicitly demonstrate their topological stability. We also review the recent experimental observation of the QSH state in HgTe/(Hg,Cd)Te QWs. We review both the fabrication of the sample and the experimental setup. For thin QWs with well width d(Qw) 6.3 nm, the insulating regime shows the conventional behavior of vanishingly small conductance at low temperature. However, for thicker QWs (d(QW) > 6.3 nm), the nominally insulating regime shows a plateau of residual conductance close to 2e(2)/h. The residual conductance is independent of the sample width, indicating that it is caused by edge states. Furthermore, the residual conductance is destroyed by a small external magnetic field. The quantum phase transition at the critical thickness, d(c) = 6.3 nm, is also independently determined from the occurrence of a magnetic field induced insulator to metal transition.},
   author = {M Konig and H Buhmann and L W Molenkamp and T Hughes and C X Liu and X L Qi and S C Zhang},
   issue = {3},
   journal = {J Phys Soc Jpn},
   keywords = {spin-orbit effects
semiconductor spintronics
band structure topology
edge channel transport
chiral-symmetry
band-structure
lattice
conductance
wells
neutrinos
absence
states
proof},
   pages = {31007},
   title = {The quantum spin Hall effect: Theory and experiment},
   volume = {77},
   year = {2008}
}
@article{Konig2007,
   abstract = {Recent theory predicted that the quantum spin Hall effect, a fundamentally new quantum state of matter that exists at zero external magnetic field, may be realized in HgTe/(Hg,Cd)Te quantum wells. We fabricated such sample structures with low density and high mobility in which we could tune, through an external gate voltage, the carrier conduction from n-type to p-type, passing through an insulating regime. For thin quantum wells with well width d < 6.3 nanometers, the insulating regime showed the conventional behavior of vanishingly small conductance at low temperature. However, for thicker quantum wells (d > 6.3 nanometers), the nominally insulating regime showed a plateau of residual conductance close to 2e(2)/h, where e is the electron charge and h is Planck's constant. The residual conductance was independent of the sample width, indicating that it is caused by edge states. Furthermore, the residual conductance was destroyed by a small external magnetic field. The quantum phase transition at the critical thickness, d = 6.3 nanometers, was also independently determined from the magnetic field-induced insulator-to-metal transition. These observations provide experimental evidence of the quantum spin Hall effect.},
   author = {M Konig and S Wiedmann and C Brune and A Roth and H Buhmann and L W Molenkamp and X L Qi and S C Zhang},
   issue = {5851},
   journal = {Science},
   keywords = {graphene
phase},
   pages = {766-770},
   title = {Quantum spin hall insulator state in HgTe quantum wells},
   volume = {318},
   year = {2007}
}
@article{Kroemer2004,
   abstract = {The three semiconductors InAs, GaSb, and AlSb form an approximately lattice-matched set around 6.1 Angstrom, covering a wide range of energy gaps and other properties. Of particular interest are heterostructures combining InAs with one or both of the antimonides, and they are emphasized in this review. In addition to their use in conventional device types (FETs, RTDs, etc.), several heterostructure configurations with unique properties have been explored, especially InAs/AlSb quantum wells and InAs/GaSb superlattices.
InAs/AlSb quantum wells are an ideal medium to study the low-temperature transport properties in InAs itself. With gate-induced electron sheet concentrations on the order 10(12) cm(-2), they exhibit a pronounced conductivity quantization. The very deep wells (1.35 eV) provide excellent electron confinement, and also permit modulation doping up to at least 10(13) electrons cm(-2). Because of the very low effective mass in InAs, heavily doped wells are essentially metals, with Fermi energies around 200 meV, and Fermi velocities exceeding 10(8) cm s(-1). Contacted with superconducting electrodes, such structures can act as superconductive weak links.
InAs/GaSb-related superlattices with their broken-gap lineup behave like semimetals at large lattice periods, but if the lattice period is shortened, increasing quantization effects cause a transition to a narrow-gap semiconductor, making such structures of interest for infrared detectors, often combined with the deliberate addition of strain. (C) 2003 Elsevier B.V. All rights reserved.},
   author = {H Kroemer},
   issue = {3-4},
   journal = {Physica E-Low-Dimensional Systems and Nanostructures},
   keywords = {heterostructures
indium arsenide
antimonides
band lineup
quantum wells
superlattices
infrared detectors
inas/alsb quantum-wells
molecular-beam epitaxy
electron concentrations
aluminum antimonide
interface roughness
gallium antimonide
infrared detectors
heterojunctions
superlattices
scattering},
   pages = {196-203},
   title = {The 6.1 angstrom family (InAs, GaSb, AlSb) and its heterostructures: a selective review},
   volume = {20},
   year = {2004}
}
@article{Kononov2015,
   abstract = {We experimentally investigate spin-polarized electron transport between two ferromagnetic contacts, placed at the edge of a two-dimensional electron system with band inversion. The system is realized in a narrow (8 nm) HgTe quantum well, the ferromagnetic side contacts are formed from a premagnetized permalloy film. In zero magnetic field, we find a significant edge current contribution to the transport between two ferromagnetic contacts. We experimentally demonstrate that this transport is sensitive to the mutual orientation of the magnetization directions of two 200 A mu m-spaced ferromagnetic leads. This is a direct experimental evidence on the spin-coherent edge transport over the macroscopic distances. Thus, the spin is extremely robust at the edge of a two-dimensional electron system with band inversion, confirming the helical spin-resolved nature of edge currents.},
   author = {A Kononov and S V Egorov and Z D Kvon and N N Mikhailov and S A Dvoretsky and E V Deviatov},
   issue = {12},
   journal = {Jetp Lett+},
   keywords = {hall regime
state
transport
contact},
   pages = {814-819},
   title = {Evidence on the macroscopic length scale spin coherence for the edge currents in a narrow HgTe quantum well},
   volume = {101},
   year = {2015}
}
@article{Kurobe1994,
   abstract = {We have studied the in-plane magnetoresistance of coupled double-quantum-well structures, in which each well has a different mobility and where the values of carrier concentration can be varied independently. Resistance resonances, observed at zero magnetic field, were suppressed with an in-plane magnetic field of 1 T, provided the field was perpendicular to the current. The magnetoresistance showed structure which changed systematically with front-gate and back-gate voltages, and was due to the deformation of both wave functions and Fermi surfaces in the in-plane magnetic field.},
   author = {A Kurobe and I M Castleton and E H Linfield and M P Grimshaw and K M Brown and D A Ritchie and M Pepper and G A C Jones},
   issue = {7},
   journal = {Phys Rev B},
   keywords = {double-quantum-well
magnetic-fields
parallel
systems
heterostructures
barrier},
   pages = {4889-4892},
   title = {Wave-Functions and Fermi Surfaces of Strongly Coupled 2-Dimensional Electron Gases Investigated by In-plane Magnetoresistance},
   volume = {50},
   year = {1994}
}
@article{Kutty2010,
   abstract = {We report on the comparison of mesa sidewall profiles of InAs/GaSb strained-layer superlattice (SLS) detector structures (lambda(50%) (cutoff) approximate to 14 mu m at V(bias) = 0 V and T = 30 K) obtained after (a) a conventional BCl3-based inductively coupled plasma etch, (b) a chemical etch (H(2)O(2):HCl:H(2)O, 1: 1: 4), and (c) a combination of both etches. We found that the smoothest sidewall profile with reasonable undercut (similar to 5 mu m) was obtained after chemical etch only. The chemical etch was optimized primarily using an n-type GaSb substrate. During this process, numerous chemical etchants were examined. GaSb n-type substrates were chosen for this study in preference over InAs substrates due to their high chemical reactivity and the complicated composition of the native oxide. In addition, SLS detectors are usually grown on GaSb substrates and, after hybridization of the focal-plane array to the readout integrated circuit, the GaSb substrate is etched away using a combination of wet and dry etching techniques. We found that H(2)O(2):HCl:H(2)O (1: 1: 4) etching solution provided the smoothest etched surface of GaSb, with a root-mean-square roughness of 1.59 nm.},
   author = {M N Kutty and E Plis and A Khoshakhlagh and S Myers and N Gautam and S Smolev and Y D Sharma and R Dawson and S Krishna and S J Lee and S K Noh},
   issue = {10},
   journal = {J Electron Mater},
   keywords = {iii-v semiconductors
strained-layer superlattice
infrared detectors
chemical treatment
surface morphology
gallium antimonide
iii-v-semiconductors
gallium antimonide
oxide-substrate
gasb
films
layer
gaas},
   pages = {2203-2209},
   title = {Study of Surface Treatments on InAs/GaSb Superlattice LWIR Detectors},
   volume = {39},
   year = {2010}
}
@article{Laikhtman1997,
   abstract = {A simple model is developed for the calculation of carrier spectrum in the presence of self-consistent potential for various kinds of quantum well systems. The model is applied to InAs/GaSb heterostructures and presents simple analytical results. The accuracy of the model is nearly equal to that of numerical models but its usage is much easier. (C) 1997 Elsevier Science Ltd.},
   author = {B Laikhtman and S deLeon and L D Shvartsman},
   issue = {5},
   journal = {Solid State Commun},
   keywords = {quantum wells
electronic band structure
quantum-well structure
electric-field
transition
transport
devices},
   pages = {257-262},
   title = {Energy spectrum of InAs/GaSb heterostructures},
   volume = {104},
   year = {1997}
}
@article{Lakrimi1997,
   abstract = {The magnetoresistance of semimetallic InAs/GaSb superlattices has been measured in parallel magnetic fields. The temperature dependence reveals for the first time the existence of a minigap at the anticrossing points between the electron and hole dispersion relations. At high magnetic fields, samples which are close to intrinsic show surprisingly large decreases in resistance of up to 70%. The magnetoresistance also depends on crystal orientation. We present a theoretical model which explains the experimental observations and estimates the minigap to be of order 7 meV.},
   author = {M Lakrimi and S Khym and R J Nicholas and D M Symons and F M Peeters and N J Mason and P J Walker},
   issue = {16},
   journal = {Phys Rev Lett},
   keywords = {resonant magnetotunneling spectroscopy
strained-layer superlattices
gasb super-lattices
dispersion-curves
quantum-well
transition
growth},
   pages = {3034-3037},
   title = {Minigaps and novel giant negative magnetoresistance in InAs/GaSb semimetallic superlattices},
   volume = {79},
   year = {1997}
}
@article{Lapushkin2004,
   abstract = {We investigate the phase transitions in InAs/GaSb quantum wells sandwiched between two wide-gap AlSb barrier layers under an external electric field perpendicular to interfaces. The Schrodinger and the Poisson equations are solved self-consistently to derive the subband dispersions, the potential profile, the electron charge distribution in the InAs layer, and the hole charge distribution in the GaSb layer. The Burt-Foreman envelope function theory and the scattering matrix method are used to solve the Schrodinger equation in the framework of the eight-band k (.) p model, including the spin-splitting of subbands in our calculation. We have found that in a thick InAs/GaSb quantum well, which has been investigated experimentally by Cooper et al (1998 Phys. Rev. B 57 11915), under low external electric fields, two electron levels stay below the highest hole level at zero in-plane wavevector k(parallel to) = 0. Then, the anticrossings of electron and hole levels produce several minigaps in the inplane dispersions, inside which the states of other subbands exist. As a result, the system is in a sernimetal phase. With increasing external electric field, the semimetal phase changes to semiconductor phase with only one hybridization gap. When all electron levels become higher than the hole levels at higher electric fields, the system has a semiconducting gap.},
   author = {I Lapushkin and A Zakharova and S T Yen and K A Chao},
   issue = {26},
   journal = {J Phys-Condens Mat},
   keywords = {gap heterostructures
band-structure
superlattices
hybridization
systems},
   pages = {4677-4684},
   title = {A self-consistent investigation of the semimetal-semiconductor transition in InAs/GaSb quantum wells under external electric fields},
   volume = {16},
   year = {2004}
}
@article{Laughlin1981,
   author = {R B Laughlin},
   issue = {10},
   journal = {Phys Rev B},
   pages = {5632-5633},
   title = {Quantized Hall Conductivity in 2 Dimensions},
   volume = {23},
   year = {1981}
}
@article{Laughlin1999,
   author = {R B Laughlin},
   issue = {4},
   journal = {Rev Mod Phys},
   keywords = {incompressible quantum fluid
non-metallic conduction
filled landau-level
magnetic-field
2 dimensions
charged excitations
low-temperatures
hall states
localization
statistics},
   pages = {863-874},
   title = {Nobel Lecture: Fractional quantization},
   volume = {71},
   year = {1999}
}
@article{Laughlin2000,
   author = {R B Laughlin},
   issue = {3},
   journal = {Usp Fiz Nauk+},
   keywords = {incompressible quantum fluid
non-metallic conduction
filled landau-level
magnetic-field
2 dimensions
charged excitations
low-temperatures
hall states
localization
statistics},
   pages = {292-303},
   title = {Fractional quantization},
   volume = {170},
   year = {2000}
}
@article{Le1998,
   abstract = {Experimental studies of the lasing efficiency of optically pumped 4-mu m GaInSb-InAs-AlSb multiple-quantum-well (MQW) lasers that emitted >1-W peak power/facet at 80 K indicated that internal loss is the main factor that limits the power output, The internal loss coefficient and internal quantum efficiency were determined bg measuring the lasing efficiency versus temperature for devices of different, facet reflec tivities and lengths. The internal loss coefficient was found to increase from similar to 18 cm(-1) near 70 K to similar to 60-100 cm(-1) near 180 K, while the internal quantum efficiency remained constant at similar to 47\% (or similar to 67\% with the correction for the finite absorption of the active region) from 70 to 130 K, The increase of internal loss and the decrease of external quantum efficiency versus temperature were found very similar to those of doable-heterostructure InAsSb-GaSb lasers and were similarly interpreted in terms of intervalence bared carrier absorption. Extrapolation of power performance for improved devices with lower internal loss indicated that high-efficiency multi-watt quasi-CW output with a broad-area brightness of similar to 1 MW/cm(2). sterad is possible.},
   author = {H Q Le and C H Lin and S J Murray and R Q Yang and S S Pei},
   issue = {6},
   journal = {Ieee J Quantum Elect},
   keywords = {laser efficiency
laser internal loss
mid-infrared lasers
narrow-gap semiconductors
quantum-well lasers
semiconductor lasers
continuous-wave operation
mu-m
room-temperature},
   pages = {1016-1030},
   title = {Effects of internal loss on power efficiency of mid-infrared InAs-GaInSb-AlSb quantum-well lasers and comparison with InAsSb lasers},
   volume = {34},
   year = {1998}
}
@article{Li2009,
   abstract = {We investigate theoretically the spin states in InAs/AlSb/GaSb broken-gap quantum wells by solving the Kane model and the Poisson equation self-consistently. The spin states in InAs/AlSb/GaSb quantum wells are quite different from those obtained by the single-band Rashba model due to the electron-hole hybridization. The Rashba spin splitting of the lowest conduction subband shows an oscillating behavior. The D'yakonov-Perel' spin-relaxation time shows several peaks with increasing the Fermi wave vector. By inserting an AlSb barrier between the InAs and GaSb layers, the hybridization can be greatly reduced. Consequently, the spin orientation, the spin splitting, and the D'yakonov-Perel' spin-relaxation time can be tuned significantly by changing the thickness of the AlSb barrier.},
   author = {J Li and W Yang and K Chang},
   issue = {3},
   journal = {Phys Rev B},
   keywords = {electron-hole system
band-structure
compound semiconductors
relaxation anisotropy
gap heterostructures
optical-transitions
ground-state
superlattices
field
hybridization},
   pages = {035303-1- 11},
   title = {Spin states in InAs/AlSb/GaSb semiconductor quantum wells},
   volume = {80},
   year = {2009}
}
@article{Li2015,
   abstract = {We report on the observation of a helical Luttinger liquid in the edge of an InAs/GaSb quantum spin Hall insulator, which shows characteristic suppression of conductance at low temperature and low bias voltage. Moreover, the conductance shows power-law behavior as a function of temperature and bias voltage. The results underscore the strong electron-electron interaction effect in transport of InAs/GaSb edge states. Because of the fact that the Fermi velocity of the edge modes is controlled by gates, the Luttinger parameter can be fine tuned. Realization of a tunable Luttinger liquid offers a one-dimensional model system for future studies of predicted correlation effects.},
   author = {T X Li and P J Wang and H L Fu and L J Du and K A Schreiber and X Y Mu and X X Liu and G Sullivan and G A Csathy and X Lin and R R Du},
   issue = {13},
   journal = {Phys Rev Lett},
   keywords = {topological insulators
transport
behavior},
   pages = {136804},
   title = {Observation of a Helical Luttinger Liquid in InAs/GaSb Quantum Spin Hall Edges},
   volume = {115},
   year = {2015}
}
@article{Lin1998,
   abstract = {An elemental Sb layer, formed at the oxide/GaSb interface, causes large surface leakage current and recombination; which are two main drawbacks of GaSb-based devices in full photoelectric application. The proportion of elemental Sb to other Sb compounds at the GaSb surface was increased by immersing the sample into diluted HCl solution. With sulfuring of the GaSb surface, elemental Sb was replaced by Sb2S5 and Sb oxides were removed. The mechanism that prevents formation of the leakage path at the as-etched GaSb surface is elucidated by X-ray photoelectron spectroscopy (XPS).},
   author = {C L Lin and Y K Su and T S Se and W L Li},
   issue = {12B},
   journal = {Jpn J Appl Phys 2},
   keywords = {gasb
sulfur passivation
xps
binding energy
gallium antimonide
electrical-properties
defects
diodes},
   pages = {L1543-L1545},
   title = {Variety transformation of compound at GaSb surface under sulfur passivation},
   volume = {37},
   year = {1998}
}
@article{Liu2011,
   abstract = {Starting from symmetry considerations and the tight-binding method in combination with first-principles calculation, we systematically derive the low-energy effective Hamiltonian involving spin-orbit coupling (SOC) for silicene. This Hamiltonian is very general because it applies not only to silicene itself but also to the low-buckled counterparts of graphene for the other group-IVA elements Ge and Sn, as well as to graphene when the structure returns to the planar geometry. The effective Hamitonian is the analog to the graphene quantum spin Hall effect (QSHE) Hamiltonian. As in the graphene model, the effective SOC in low-buckled geometry opens a gap at the Dirac points and establishes the QSHE. The effective SOC actually contains the first order in the atomic intrinsic SOC strength xi(0), while this leading-order contribution of SOC vanishes in the planar structure. Therefore, silicene, as well as the low-buckled counterparts of graphene for the other group-IVA elements Ge and Sn, has a much larger gap opened by the effective SOC at the Dirac points than graphene, due to the low-buckled geometry and larger atomic intrinsic SOC strength. Further, the more buckled is the structure, the greater is the gap. Therefore, the QSHE can be observed in low-buckled Si, Ge, and Sn systems in an experimentally accessible temperature regime. In addition, the Rashba SOC in silicene is intrinsic due to its own low-buckled geometry, which vanishes at the Dirac point K, while it has a nonzero value with deviation of (k) over right arrow from the K point. Therefore, the QSHE in silicene is robust against the intrinsic Rashba SOC.},
   author = {C C Liu and H Jiang and Y G Yao},
   issue = {19},
   journal = {Phys Rev B},
   keywords = {hgte quantum-wells
topological insulators
graphene},
   title = {Low-energy effective Hamiltonian involving spin-orbit coupling in silicene and two-dimensional germanium and tin},
   volume = {84},
   year = {2011}
}
@article{Liu2008,
   abstract = {The quantum spin Hall (QSH) state is a topologically nontrivial state of quantum matter which preserves time-reversal symmetry; it has an energy gap in the bulk, but topologically robust gapless states at the edge. Recently, this novel effect has been predicted and observed in HgTe quantum wells and in this Letter we predict a similar effect arising in Type-II semiconductor quantum wells made from InAs/GaSb/AlSb. The quantum well exhibits an "inverted" phase similar to HgTe/CdTe quantum wells, which is a QSH state when the Fermi level lies inside the gap. Due to the asymmetric structure of this quantum well, the effects of inversion symmetry breaking are essential. Remarkably, the topological quantum phase transition between the conventional insulating state and the quantum spin Hall state can be continuously tuned by the gate voltage, enabling quantitative investigation of this novel phase transition.},
   author = {C X Liu and T L Hughes and X L Qi and K Wang and S C Zhang},
   issue = {23},
   journal = {Phys Rev Lett},
   keywords = {gasb super-lattices
phase-transition
wells
hybridization
gap},
   pages = {236601},
   title = {Quantum spin Hall effect in inverted Type-II semiconductors},
   volume = {100},
   year = {2008}
}
@article{Liu1998,
   abstract = {To investigate the cascade process, we study two sets of mid-infrared InAs/GaInSb/AlSb multiple quantum well electroluminescent devices, Each set has nominally the same device parameters, differing only by the number of periods. We find, as expected, that for the same driving current the larger the device period the more intense is the emission. We also find that the scaling is far from ideal. We correlate the deviation of the exact scaling with the variation of the wafer-to-wafer structural quality.},
   author = {H C Liu and E Dupont and J P McCaffrey and M Buchanan and D Zhang and R Q Yang and C H Lin and S J Murry and S S Pei},
   journal = {In-Plane Semiconductor Lasers: From Ultraviolet to Mid-Infrared Ii},
   keywords = {cascade
infrared
inas
gasb
alsb},
   pages = {318-324},
   title = {Mid-infrared interband cascade emission in InAs/GaInSb/AlSb type-II heterostructures},
   volume = {3284},
   year = {1998}
}
@article{Lo1992,
   abstract = {We have measured the Shubnikov-de Haas (SdH) effect in the Al0.6Ga0.4Sb/InAs quantum wells under the negative persistent photoconductivity (NPPC) conductions. By illuminating the sample at low-temperature, the carrier concentration of the two-dimensional electron gas in the InAs well was reduced from 5.8 to 3.6 X 10(11) cm-2 and the corresponding quantum lifetime increases from 0.16 to 0.21 ps. The electrons which escaped from the InAs well were captured by the ionized deep donors in the Al0.6Ga0.4Sb layers. The effective mass is equal to (0.0317 +/- 0.0005)m0. We also propose, based on the SdH data, that the illumination of the sample with the ionized deep donors at low temperature will exhibit the NPPC effect.},
   author = {I Lo and W C Mitchel and M O Manasreh and C E Stutz and K R Evans},
   issue = {6},
   journal = {Appl Phys Lett},
   keywords = {electron concentrations
heterostructures
scattering
transport
time},
   pages = {751-753},
   title = {Negative Persistent Photoconductivity in the Al_0.6Ga_0.4Sb/InAs Quantum-Wells},
   volume = {60},
   year = {1992}
}
@article{Lo1993,
   author = {I Lo and W C Mitchel and C E Stutz and M Y Yen},
   journal = {Semiconductor Heterostructures for Photonic and Electronic Applications},
   pages = {31-36},
   title = {The Negative Persistent Photoconductivity in the Deep Quantum-Wells},
   volume = {281},
   year = {1993}
}
@article{Lubell1983,
   author = {M S Lubell},
   issue = {3},
   journal = {Ieee T Magn},
   pages = {754-757},
   title = {Empirical Scaling Formulas for Critical Current and Critical-Field for Commercial NbTi},
   volume = {19},
   year = {1983}
}
@article{Luo1990,
   author = {J Luo and H Munekata and F F Fang and P J Stiles},
   issue = {11},
   journal = {Phys Rev B},
   pages = {7685-7693},
   title = {Effects of Inversion Asymmetry on Electron-Energy Band Structures in GaSb/InAs/GaSb Quantum-Wells},
   volume = {41},
   year = {1990}
}
@article{Luryi1988,
   author = {S Luryi},
   issue = {6},
   journal = {Appl Phys Lett},
   pages = {501-503},
   title = {Quantum Capacitance Devices},
   volume = {52},
   year = {1988}
}
@article{Maciejko2010,
   abstract = {We study numerically the edge magnetoconductance of a quantum spin Hall insulator in the presence of quenched nonmagnetic disorder. For a finite magnetic field B and disorder strength W on the order of the bulk gap E(g), the conductance deviates from its quantized value in a manner which appears to be linear in vertical bar B vertical bar at small B. The observed behavior is in qualitative agreement with the cusplike features observed in recent magneto-transport measurements on HgTe quantum wells. We propose a dimensional crossover scenario as a function of W, in which for weak disorder W<E(g) the edge liquid is analogous to a disordered spinless one-dimensional (1D) quantum wire, while for strong disorder W>E(g), the disorder causes frequent virtual transitions to the two-dimensional (2D) bulk, where the originally 1D edge electrons can undergo 2D diffusive motion and 2D antilocalization.},
   author = {J Maciejko and X L Qi and S C Zhang},
   issue = {15},
   journal = {Phys Rev B},
   keywords = {disordered wires
symplectic symmetry
localization
transport
wells},
   title = {Magnetoconductance of the quantum spin Hall state},
   volume = {82},
   year = {2010}
}
@article{Makarovskii2000,
   abstract = {Bilayer two-dimensional electron systems formed by a thin barrier in the GaAs buffer of a standard heterostructure were investigated by magnetotransport measurements. In magnetic fields oriented parallel to the electron layers, the magnetoresistance exhibits an oscillation associated with the depopulation of the higher occupied subband and the field-induced transition into a decoupled bilayer. Shubnikov-de Haas oscillations in slightly tilted magnetic fields allow us to reconstruct the evolution of the electron concentration in the individual subbands as a function of the in-plane magnetic field. The characteristics of the system derived experimentally are in quantitative agreement with numerical self-consistent field calculations of the electronic structure.},
   author = {O N Makarovskii and L Smrcka and P Vasek and T Jungwirth and M Cukr and L Jansen},
   issue = {16},
   journal = {Phys Rev B},
   keywords = {inplane magnetoresistance
fermi-surface
subject
parallel
systems
mass
heterostructures
depopulation
capacitance
conductance},
   pages = {10908-10913},
   title = {Magnetoresistance and electronic structure of asymmetric GaAs/Al_0.3Ga_0.7As double quantum wells in an in-plane or tilted magnetic field},
   volume = {62},
   year = {2000}
}
@article{Marcinkiewicz2015,
   abstract = {We report terahertz measurements on bulk HgCdTe crystals at the semiconductor-to-semimetal topological transition and InAs/GaSb inverted band structure quantum well. We show that physical parameters of these narrow gap systems driven in specific topological phases can be efficiently extracted by means of terahertz photoconductivity studies.},
   author = {M Marcinkiewicz and F Teppe and C Consejo and N Dyakonova and W Desrat and D Coquillat and S Ruffenach and W Knap and N N Mikhailov and S A Dvoretskii and F Gonzalez-Posada and J B Rodriguez and E Tournie},
   journal = {J Phys Conf Ser},
   keywords = {quantum-wells
heterostructures},
   title = {Terahertz studies of 2D and 3D topological transitions},
   volume = {647},
   year = {2015}
}
@article{Marlow1999,
   abstract = {The contributions of wave function hybridization and spontaneous exciton formation to the ground state of closely spaced electron and hole gases in InAs/GaSb heterostructures were investigated using cyclotron resonance (CR) spectroscopy. Strongly hybridized samples exhibit two electronlike CR absorptions at all perpendicular magnetic fields. The high frequency mode neither disappears at high temperatures (similar to 100 K) nor is affected by changes in electron or hole density, but is eliminated by a high parallel magnetic field (similar to 7 T). These effects can be understood as signatures of electron-hole wave function hybridization, and cannot be explained in terms of an excitonic gas.},
   author = {T P Marlow and L J Cooper and D D Arnone and N K Patel and D M Whittaker and E H Linfield and D A Ritchie and M Pepper},
   issue = {11},
   journal = {Phys Rev Lett},
   keywords = {quantum-wells
transition},
   pages = {2362-2365},
   title = {Ground state of a two-dimensional coupled electron-hole gas in InAs/GaSb narrow gap heterostructures},
   volume = {82},
   year = {1999}
}
@article{Meijer1953,
   author = {H J G Meijer and D Polder},
   issue = {2},
   journal = {Physica},
   pages = {255-264},
   title = {Note on Polar Scattering of Conduction Electrons in Regular Crystals},
   volume = {19},
   year = {1953}
}
@article{Meijer1960,
   author = {P H E Meijer},
   issue = {1},
   journal = {Physica},
   pages = {61-65},
   title = {A Group Theoretical Proof of Kramers Theorem},
   volume = {26},
   year = {1960}
}
@article{Mi2013,
   abstract = {We show how a quantum dot with a ballistic single-channel point contact to a superconductor can be created by means of a gate electrode at the edge of a quantum spin Hall insulator (such as an InAs/GaSb quantum well). A weak perpendicular magnetic field traps a Majorana zero mode, so that it can be observed in the gate-voltage-averaged differential conductance < dI/dV > as a 4e(2)/h zero-bias peak above a (2/3 pi(2) - 4)e(2)/h background. The one-dimensional edge does not permit the braiding of pairs of Majorana fermions, but this obstacle can be overcome by coupling opposite edges at a constriction, allowing for a demonstration of non-Abelian statistics.},
   author = {S Mi and D I Pikulin and M Wimmer and C W J Beenakker},
   issue = {24},
   journal = {Phys Rev B},
   keywords = {topological insulators
matrix theory
transport
wells
state},
   title = {Proposal for the detection and braiding of Majorana fermions in a quantum spin Hall insulator},
   volume = {87},
   year = {2013}
}
@article{Millard1996,
   abstract = {Double layer structures have been used to measure the compressibility of both two-dimensional electron (2DEG) and two-dimensional hole gases (2DHG). This has been achieved by making independent contacts to the lower layer and using it to detect the compressibility of the upper layer. Both positive and negative compressibilities are observed, with the negative compressibility enhanced for hole gases, where the changes of the interaction energy are larger than those of the kinetic energy. The negative compressibility of the top layer leads to a charge transfer between the layers; this has been modelled and gives good agreement with the experiments when exchange and correlation is included. Due to disorder in the layers, however, the model deviates from the experimental results close to depletion. The dependence of the charge transfer upon distance between the electron gases has also been studied, with the charge transfer decreasing linearly with increasing spacing between the 2DEGs. This suggests that inter-layer interactions are insignificant. (C) 1996 American Institute of Physics.},
   author = {I S Millard and N K Patel and M Y Simmons and E H Linfield and D A Ritchie and G A C Jones and M Pepper},
   issue = {23},
   journal = {Appl Phys Lett},
   keywords = {quantum-well},
   pages = {3323-3325},
   title = {Compressibility studies of double electron and double hole gas systems},
   volume = {68},
   year = {1996}
}
@article{Mittag2017,
   abstract = {We investigate different methods of passivating sidewalls of wet etched InAs heterostructures in order to suppress inherent edge conduction that is presumed to occur due to band bending at the surface, leading to charge carrier accumulation. Passivation techniques including sulfur, positively charged compensation dopants, and plasma enhanced chemical vapor deposition of SiNx do not show an improvement. Surprisingly, atomic layer deposition of Al2O3 leads to an increase in the edge resistivity of more than an order of magnitude. While the mechanism behind this change is not fully understood, possible reasons are suggested. Published by AIP Publishing.},
   author = {C Mittag and M Karalic and S Mueller and T Tschirky and W Wegscheider and O Nazarenko and M V Kovalenko and T Ihn and K Ensslin},
   issue = {8},
   journal = {Appl Phys Lett},
   keywords = {atomic layer deposition
grown inas(001) surfaces
electron accumulation
reducing agent
thin-films
nanowires
trimethylaluminum
oxides
gaas},
   pages = {82101},
   title = {Passivation of edge states in etched InAs sidewalls},
   volume = {111},
   year = {2017}
}
@article{Moore1966,
   author = {T W Moore},
   issue = {13},
   journal = {Phys Rev Lett},
   pages = {581-583},
   title = {Cyclotron Resonance Linewidths and Electron Relaxation Times in Gallium},
   volume = {16},
   year = {1966}
}
@article{Mott1961,
   author = {N F Mott},
   issue = {62},
   journal = {Philos Mag},
   pages = {287-309},
   title = {The Transition to the Metallic State},
   volume = {6},
   year = {1961}
}
@article{Mu1999,
   abstract = {To investigate InAs/GaInSb/AlSb type-II mid-Hi interband cascade lasers, an eight-band k . p model with envelope function approximation is used to compute band structures, wavefunctions, and optical transition matrix elements. The equation for multi-component envelope functions is solved by the finite element method. The strain effect is treated by Pikus-Bir method and the terms up to second order of wavevector are included. The possible non-uniform electric field effect in the cascade laser structure is considered appropriately. The optical gain, radiative current density, internal loss due to intervalence subband transitions are obtained as the function of injection carrier density in the cascade laser at different temperatures. The implications of our calculated results on device performance are discussed.},
   author = {Y M Mu and R Q Yang},
   journal = {Physics and Simulation of Optoelectronic Devices Vii},
   keywords = {modeling
interband cascade laser
eight-band k.p model
envelope-function approximation
finite-element analysis
quantum-wells
intersubband transitions
potential profiles
semiconductors
superlattices},
   pages = {811-822},
   title = {Modeling of InAs/GaInSb/AlSb type-II mid-IR interband cascade lasers},
   volume = {3625},
   year = {1999}
}
@article{Mueller2015,
   abstract = {We have investigated low-temperature electronic transport on InAs/GaSb double quantum wells, a system which promises to be electrically tunable from a normal to a topological insulator. Hall bars of 50 mu m in length down to a few micrometers gradually develop a pronounced resistance plateau near charge neutrality, which comes along with distinct nonlocal transport along the edges. Plateau resistances are found to be above or below the quantized value expected for helical edge channels. We discuss these results based on the interplay between imperfect edges and residual local bulk conductivity.},
   author = {S Mueller and A N Pal and M Karalic and T Tschirky and C Charpentier and W Wegscheider and K Ensslin and T Ihn},
   issue = {8},
   journal = {Phys Rev B},
   keywords = {band-structure
superlattices
hybridization
transition
systems
gasb
gap},
   pages = {81303},
   title = {Nonlocal transport via edge states in InAs/GaSb coupled quantum wells},
   volume = {92},
   year = {2015}
}
@book{Myers1997,
   author = {H P Myers},
   edition = {2nd},
   keywords = {Solid state physics.},
   pages = {xiii, 522 p.},
   publisher = {Taylor \& Francis},
   title = {Introductory solid state physics},
   year = {1997}
}
@article{Nakai2017,
   abstract = {We extend Laughlin's magnetic-flux-threading argument to the quantized thermal Hall effect. A proper analog of Laughlin's adiabatic magnetic-flux threading process for the case of the thermal Hall effect is given in terms of an external gravitational field. From the perspective of the edge theories of quantum Hall systems, the quantized thermal Hall effect is closely tied to the breakdown of large diffeomorphism invariance, that is, a global gravitational anomaly. In addition, we also give an argument from the bulk perspective in which a free energy, decomposed into its Fourier modes, is adiabatically transferred under an adiabatic process involving external gravitational perturbations.},
   author = {R Nakai and S Ryu and K Nomura},
   issue = {16},
   journal = {Phys Rev B},
   keywords = {2 dimensions
topological insulators
transport
states
conductivity},
   pages = {165405},
   title = {Laughlin's argument for the quantized thermal Hall effect},
   volume = {95},
   year = {2017}
}
@article{Naveh2001,
   abstract = {The carriers in InAs-GaSb double quantum wells are hybrid electron-holes. We study the magnetotransport properties of such particles using a two-component Keldysh technique, which results in a semi-analytic expression for the small-field current. This approach is necessary for calculating the zero-temperature current, which is large even when the Fermi energy lies within the hybridization gap ( in a semiclassical ( Boltzmann) approach this current vanishes). Magnetic-field dependence of the conductance is also affected significantly by the hybridization of electrons and holes.},
   author = {Y Naveh and B Laikhtman},
   issue = {4},
   journal = {Europhys Lett},
   keywords = {quantum-wells
inas/gasb heterostructures
resistance resonance
band-structure
hybridization
gas
magnetoresistance
superlattices
systems},
   pages = {545-551},
   title = {Magnetotransport of coupled electron-holes},
   volume = {55},
   year = {2001}
}
@book{,
   author = {Donald A Neamen},
   keywords = {Semiconductors.},
   pages = {xx, 746 pages},
   title = {Semiconductor physics and devices : basic principles}
}
@article{Negrila2016,
   abstract = {The depth composition of the thin layer alloy, AuGeNi, devoted to acting as an ohmic contact on n-GaAs(110) has been investigated by in situ XPS combined with Argon ion sputtering techniques. The fresh cleaved surfaces, supposed to be free of oxygen, were usually deposited with a 200nm metallic layer in high vacuum conditions (better than 10(-7) torr), by thermal evaporation, and annealed at a 430-450 degrees Celsius temperature for 5 minutes. About 18 sessions of ion Ar surfaces etching and intermediate XPS measurements were performed in order to reveal the border of the metal/semiconductor interface. The atomic concentrations of the chemical elements have been approximated. Au4f, Ga3d, Ga2p, As3d, As2p, Ni2p(3/2), Ge3d, O1s, and C1s spectral lines were recorded. The Au, Ge, and Ni have a homogenous distribution while Ga and As tend to diffuse to the surface. Oxygen is present in the first layers of the surface while carbon completely disappears after the second etching step. The existence of an Au-Ga alloy was detected and XPS spectra show only metal Ni and Ge within the layer and at the interface. We tried to perform a study about the depth chemical composition profile analysis of AuGeNi layer on cleaved n-GaAs(110) by X-Ray Photoelectron Spectroscopy (XPS) technique.},
   author = {C C Negrila and M F Lazarescu and C Logofatu and C Cotirlan and R V Ghita and F Frumosu and L Trupina},
   journal = {J Nanomater},
   keywords = {ray photoelectron-spectroscopy
auger-electron-spectroscopy
compound semiconductors
gallium-arsenide
ohmic contact
gaas
oxidation
germanium
alloys
oxides},
   pages = {7574526},
   title = {XPS Analysis of AuGeNi/Cleaved GaAs(110) Interface},
   year = {2016}
}
@article{Nguyen2015,
   abstract = {We report a backgated InAs/GaSb double quantum well device grown on GaSb substrate. The use of the native substrate allows for high materials quality with electron mobility in excess of 500 000 cm(2)/Vs at sheet charge density of 8 x 10(11) cm(2) and approaching 100 000 cm(2)/Vs near the charge neutrality point. Lattice matching between the quantum well structure and the substrate eliminates the need for a thick buffer, enabling large back gate capacitance and efficient coupling with the conduction channels in the quantum wells. As a result, quantum Hall effects are observed in both electron and hole regimes across the hybridization gap. (C) 2015 AIP Publishing LLC.},
   author = {B M Nguyen and W Yi and R Noah and J Thorp and M Sokolich},
   issue = {3},
   journal = {Appl Phys Lett},
   keywords = {band-structure
superlattice
heterojunctions
hybridization
performance
transition
resonance
systems},
   pages = {32107},
   title = {High mobility back-gated InAs/GaSb double quantum well grown on GaSb substrate},
   volume = {106},
   year = {2015}
}
@article{Nguyen1993,
   abstract = {Low-temperature mobilities in InAs-AlSb quantum wells depend sensitively on the buffer layer structures. Reflection high energy electron diffraction and x-ray diffraction show that the highest crystalline quality and best InAs transport properties are obtained by a buffer layer sequence GaAs –> AlAs –> AlSb –> GaSb, with a final GaSb layer thickness of at least 1 mum. Using the improved buffer scheme, mobilities exceeding 600,000 cm2/Vs at 10 K are routinely obtained. Modulation delta-doping with tellurium has yielded electron sheet concentrations up to 8 x 10(12) cm-2 while maintaining mobilities approaching 100,000 cm2/Vs at low temperatures.},
   author = {C Nguyen and B Brar and C R Bolognesi and J J Pekarik and H Kroemer and J H English},
   issue = {2},
   journal = {J Electron Mater},
   keywords = {inas-alsb quantum wells
interface roughness
reflection high energy electronic diffraction (rheed)
tellurium doping
transport-properties
aluminum antimonide
gallium antimonide
interface},
   pages = {255-258},
   title = {Growth of InAs-AlSb Quantum-Wells Having Both High Mobilities and High-Concentrations},
   volume = {22},
   year = {1993}
}
@article{Nichele2014,
   abstract = {We present transport measurements performed in InAs/GaSb double quantum wells. At the electron-hole crossover tuned by a gate voltage, a strong increase in the longitudinal resistivity is observed with increasing perpendicular magnetic field. Concomitantly with a local resistance exceeding the resistance quantum by an order of magnitude, we find a pronounced nonlocal resistance signal of almost similar magnitude. The coexistence of these two effects is reconciled in a model of counterpropagating and dissipative quantum Hall edge channels providing backscattering, shorted by a residual bulk conductivity.},
   author = {F Nichele and A N Pal and P Pietsch and T Ihn and K Ensslin and C Charpentier and W Wegscheider},
   issue = {3},
   journal = {Phys Rev Lett},
   keywords = {electron-hole system
band-structure
heterostructures},
   pages = {36802},
   title = {Insulating State and Giant Nonlocal Response in an InAs/GaSb Quantum Well in the Quantum Hall Regime},
   volume = {112},
   year = {2014}
}
@article{Nichele2016,
   abstract = {Wepresent transport and scanning SQUID measurements on InAs/GaSb double quantum wells, a system predicted to be a two-dimensional topological insulator. Top and back gates allow independent control of density and band offset, allowing tuning from the trivial to the topological regime. In the trivial regime, bulk conductivity is quenched but transport persists along the edges, superficially resembling the predicted helical edge-channels in the topological regime. Wecharacterize edge conduction in the trivial regime in a wide variety of sample geometries and measurement configurations, as a function of temperature, magnetic field, and edge length. Despite similarities to studies claiming measurements of helical edge channels, our characterization points to a non-topological origin for these observations.},
   author = {F Nichele and H J Suominen and M Kjaergaard and C M Marcus and E Sajadi and J A Folk and F M Qu and A J A Beukman and F K de Vries and J van Veen and S Nadj-Perge and L P Kouwenhoven and B M Nguyen and A A Kiselev and W Yi and M Sokolich and M J Manfra and E M Spanton and K A Moler},
   journal = {New J Phys},
   keywords = {quantum spin hall effect
topological insulator
scanning squid
inas/gasb
hgte quantum-wells
heterostructures
accumulation
surfaces
systems
state
gap},
   pages = {83005},
   title = {Edge transport in the trivial phase of InAs/GaSb},
   volume = {18},
   year = {2016}
}
@article{Nilsson2008,
   author = {J Nilsson and A R Akhmerov and C W J Beenakker},
   issue = {12},
   journal = {Phys Rev Lett},
   keywords = {metal-superconductor junctions
shot-noise
insulator},
   title = {Splitting of a Cooper pair by a pair of Majorana bound states},
   volume = {101},
   year = {2008}
}
@article{Nilsson2006,
   abstract = {Using the eight-band k center dot p model and the Burt-Foreman envelope function theory to perform self-consistent calculations, we have studied the effect of electron-hole hybridization on the cyclotron masses m(*) and the effective g-factors g(*) of two-dimensional quasiparticles in InAs/GaSb quantum wells under a magnetic field applied perpendicular to the interfaces. We can modify the degree of hybridization by changing the InAs and/or GaSb layer width, or by inserting a thin AlSb barrier. While electron-light-hole hybridization dominates at both low and high fields, due to a sequence of anticrossings between electronlike and heavy-holelike levels, there is also an important contribution from heavy-hole states to the strong hybridization in the intermediate field range. The field-dependence of the hybridized energy eigenstates is manifested in the variations of m(*) and g(*). Characteristic discontinuous changes of both m(*) and g(*) appear at each anticrossing, resulting in a magnetic-field-driven oscillating behavior of these quantities for electronlike states of a given Landau level index. The electron g-factor can change sign when two eigenstates anticross. Hybridization of electron and hole states enhances the electron effective mass, and we have found a complicated dependence of this effect on the interaction strength. Without inserting an AlSb barrier, the strong interaction between the electronlike and the light-holelike states at low magnetic fields produces a large level repulsion, and hence relatively small effective masses and g-factors associated with these states. Intermediate interaction leads to weaker level repulsion and therefore very heavy electron cyclotron masses as well as large g-factors associated with the lowest Landau levels. A weak interaction only enhances the cyclotron masses of the electronlike states slightly. The hole effective masses change with both the magnetic field and the sample structure in a more complicated fashion.},
   author = {K Nilsson and A Zakharova and I Lapushkin and S T Yen and K A Chao},
   issue = {7},
   journal = {Phys Rev B},
   keywords = {broken-gap heterostructures
gasb super-lattices
band-structures
resonance
magnetoabsorption
superlattices
transition},
   pages = {075308 },
   title = {Cyclotron masses and g-factors of hybridized electron-hole states in InAs/GaSb quantum wells},
   volume = {74},
   year = {2006}
}
@article{Nitta1997,
   abstract = {We have confirmed that a spin-orbit interaction in an inverted In0.53Ga0.47As/In0.52Al0.48As quantum well can be controlled by applying a gate voltage. This result shows that the spin-orbit interaction of a two-dimensional electron gas depends on the surface electric field. The dominant mechanism for the change in the spin-orbit interaction parameter can be attributed to the Rashba term. This inverted In0.53Ga0.47As/In0.52Al0.48As heterostructure is one of the promising materials for the spin-polarized field effect transistor which is proposed by Datta and Das [Appl. Phys, Lett. 56, 665 (1990)].},
   author = {J Nitta and T Akazaki and H Takayanagi and T Enoki},
   issue = {7},
   journal = {Phys Rev Lett},
   keywords = {gasb quantum-wells
inversion asymmetry
precession
layers
gaas},
   pages = {1335-1338},
   title = {Gate control of spin-orbit interaction in an inverted In_(0.53)Ga_(0.47)As/ In_(0.52)Al_(0.48)As heterostructure},
   volume = {78},
   year = {1997}
}
@article{Nitta1998,
   abstract = {We have confirmed by analyzing beating patterns of Shubnikov-de Haas oscillations that a spin-orbit interaction of the conduction band in an InAs-inserted In0.53Ga0.47As/In0.52Al0.48As heterostructure can be controlled by applying the gate voltage. The change in the spin-orbit interaction can be attributed to the Rashba term. Comparison with an In0.53Ga0.47As/In0.52Al0.48As heterostructure reveals that the spin-orbit interaction in the InAs-inserted system is more sensitive to the carrier concentration. (C) 1998 Elsevier Science B.V. All rights reserved.},
   author = {J Nitta and T Akazaki and H Takayanagi and T Enoki},
   issue = {1-4},
   journal = {Physica E},
   keywords = {spin-orbit interaction
inas-inserted ingaas/inalas heterostructure
ingaas/inalas heterostructure
quantum-wells
b->0},
   pages = {527-531},
   title = {Gate control of spin-orbit interaction in an InAs-inserted In0.53Ga0.47As/In0.52Al0.48As heterostructure},
   volume = {2},
   year = {1998}
}
@article{Nogaret1993,
   abstract = {We investigated interband tunneling transport through a hole well in five GaSb/AlSb/GaSb/AlSb/InAs type II tunnel devices in which the effect of the variation of barrier and well widths is systematically studied. Low temperature measurements were performed using high magnetic fields applied perpendicular to the current and hydrostatic pressures as external perturbations. A resonant current through the ground heavy hole subband in the GaSb well could be identified for the first time. This examination points out (i) the role of in-plane momentum conservation in determining the resonance onset voltage, and (ii) the occurrence of a shoulder in the current when a maximum of states conducts through a resonant subband.},
   author = {A Nogaret and M A Maldonado and R E Carnahan and K P Martin and R J Higgins and D K Maude and J C Portal and L A Cury and J F Chen and A Y Cho},
   issue = {10},
   journal = {J Appl Phys},
   keywords = {heterostructures},
   pages = {6443-6445},
   title = {Interband Tunneling through a Heavy-Hole State},
   volume = {74},
   year = {1993}
}
@article{Nosho2002,
   abstract = {We have compared the surface morphology of GaSb homoepitaxial films grown on both flat and I vicinal [miscut towards (111)A] (001) substrates using atomic force microscopy and scanning tunneling microscopy. Mound formation is observed for GaSb homoepitaxy on the flat substrates over a range of growth temperatures when either Sb-2 or Sb-4 is used to supply the group V flux. At sufficiently high growth temperatures, which are different depending on whether Sb-2 or Sb-4 is used, the mounds transform into fairly well-defined pyramids comprised of distinctly stacked layers that are clearly separated by monolayer-height steps. Furthermore, at the tops of the pyramids are sharp, tower-like features that are similar to15Angstrom in height. Mounds also appear during homoepitaxy on the vicinal substrates at lower growth temperatures; however, both mounds and pyramids can be suppressed when using either Sb-2 or Sb-4 by growing at temperatures above similar to400degreesC. We discuss and compare qualitatively the shape of the observed mounds with predictions of evolving morphology based on models of unstable epitaxial growth. (C) 2002 Elsevier Science B.V. All rights reserved.},
   author = {B Z Nosho and B R Bennett and E H Aifer and M Goldenberg},
   issue = {1-3},
   journal = {J Cryst Growth},
   keywords = {atomic force microscopy
surface structure
molecular beam epitaxy
antimonides
molecular-beam epitaxy
arsenic incorporation kinetics
edge diffusion
gaas
gaas(001)
instabilities
evolution
antimony
model},
   pages = {155-164},
   title = {Surface morphology of homoepitaxial GaSb films grown on flat and vicinal substrates},
   volume = {236},
   year = {2002}
}
@article{Olesberg2001,
   abstract = {Despite recent progress in electronic structure engineering of type-II materials for mid-infrared lasers, suppression of Auger recombination at room temperature has been limited. We present an active region design, consisting of AlAsSb/InAs/GaInSb/InAs/AlAsSb wells separated by an InAs/AlGaSb superlattice, that overcomes this limitation. The 300 K calculated Auger recombination rate in this structure at the optimal lasing density is five times smaller than typical Shockley-Read-Hall (defect-assisted) recombination rates. An integrated separate confinement heterostructure design suitable for this active region is also described. The separate confinement region, which is a lightly doped InAs/AlGaSb superlattice, provides efficient hole transport and injection into the active region. For an estimated nonactive region modal cavity loss of 20 cm(-1) and an optical mode width of 1.3 mum, the calculated internal threshold current density is 100 A/cm(2) at 300 K for a single quantum well device. (C) 2001 American Institute of Physics.},
   author = {J T Olesberg and M E Flatte and T C Hasenberg and C H Grein},
   issue = {6},
   journal = {J Appl Phys},
   keywords = {quantum-well lasers
multilayer superlattice lasers
mu-m
theoretical performance
midinfrared lasers
active regions
optimization
power
recombination
inas/ingasb},
   pages = {3283-3289},
   title = {Mid-infrared InAs/GaInSb separate confinement heterostructure laser diode structures},
   volume = {89},
   year = {2001}
}
@article{Orr2008,
   abstract = {The mobility and carrier concentration of a number of InSb-based modulation-doped quantum well heterostructures are examined over a range of temperatures between 4.5 and 300 K. Wide well (30 nm) and narrow well (15 nm) structures are measured. The temperature dependent mobilities are considered within a scattering model that incorporates polar optical and acoustic phonon scatterings, interface roughness scattering, and scattering from charged impurities both in the three-dimensional background and within a distributed "quasi-two-dimensional" doping layer. Room temperature mobilities as high as 51 000 cm(2)/V s are reported for heterostructures with a carrier concentration of 5.8 x 10(11) cm(-2), while low-temperature mobility (below 40 K) reaches 248 000 cm(2)/V s for a carrier concentration of 3.9 x 10(11) cm(-2). A Schrodinger-Poisson model is used to calculate band structures in the material and is shown to accurately predict carrier concentrations over the whole temperature range. Low-temperature mobility is shown to be dominated by remote ionized impurity scattering in wide well samples and by a combination of ionized impurity and interface roughness scattering in narrow well samples.},
   author = {J M S Orr and A M Gilbertson and M Fearn and O W Croad and C J Storey and L Buckle and M T Emeny and P D Buckle and T Ashley},
   issue = {16},
   journal = {Phys Rev B},
   keywords = {interface roughness scattering
phonon-scattering
high-mobility
transistor
density},
   pages = {165334},
   title = {Electronic transport in modulation-doped InSb quantum well heterostructures},
   volume = {77},
   year = {2008}
}
@article{Orth2013,
   abstract = {We consider two helical liquids on opposite edges of a two-dimensional topological insulator, which are connected by one or several local tunnel junctions. In the presence of spatially inhomogeneous Rashba spin-orbit coupling, the spin of the helical edge states is momentum dependent, and this spin texture can be different on opposite edges. We demonstrate that this has a strong impact on the electron transport between the edges. In particular, in the case of many random tunnel contacts, the localization length depends strongly on the spin textures of the edge states.},
   author = {C P Orth and G Strubi and T L Schmidt},
   issue = {16},
   journal = {Phys Rev B},
   keywords = {topological insulators},
   title = {Point contacts and localization in generic helical liquids},
   volume = {88},
   year = {2013}
}
@article{Ortiz2016,
   abstract = {We study the helical edge states of a two-dimensional topological insulator without axial spin symmetry due to the Rashba spin-orbit interaction. Lack of axial spin symmetry can lead to so-called generic helical edge states, which have energy-dependent spin orientation. This opens the possibility of inelastic backscattering and thereby nonquantized transport. Here we find analytically the new dispersion relations and the energy dependent spin orientation of the generic helical edge states in the presence of Rashba spin-orbit coupling within the Bernevig-Hughes-Zhang model, for both a single isolated edge and for a finite width ribbon. In the single-edge case, we analytically quantify the energy dependence of the spin orientation, which turns out to be weak for a realistic HgTe quantum well. Nevertheless, finite size effects combined with Rashba spin-orbit coupling result in two avoided crossings in the energy dispersions, where the spin orientation variation of the edge states is very significantly increased for realistic parameters. Finally, our analytical results are found to compare well to a numerical tight-binding regularization of the model.},
   author = {L Ortiz and R A Molina and G Platero and A M Lunde},
   issue = {20},
   journal = {Phys Rev B},
   keywords = {hgte quantum-wells
neutrinos
absence
lattice
proof},
   pages = {205431},
   title = {Generic helical edge states due to Rashba spin-orbit coupling in a topological insulator},
   volume = {93},
   year = {2016}
}
@article{Pal2015,
   abstract = {We report the electronic characterization of mesoscopic Hall bar devices fabricated from coupled InAs/GaSb quantum wells sandwiched between AlSb barriers, an emerging candidate for two-dimensional topological insulators. The electronic width of the etched structures was determined from the low field magneto-resistance peak, a characteristic signature of partially diffusive boundary scattering in the ballistic limit. In case of dry-etching the electronic width was found to decrease with electron density. In contrast, for wet etched devices it stayed constant with density. Moreover, the boundary scattering was found to be more specular for wet-etched devices, which may be relevant for studying topological edge states. (C) 2015 Author(s).},
   author = {A N Pal and S Muller and T Ihn and K Ensslin and T Tschirky and C Charpentier and W Wegscheider},
   issue = {7},
   journal = {Aip Adv},
   keywords = {phase-transition
channels
inas/alsb
wires},
   pages = {77106},
   title = {Influence of etching processes on electronic transport in mesoscopic InAs/GaSb quantum well devices},
   volume = {5},
   year = {2015}
}
@article{Pan2013,
   abstract = {We present here our recent quantum transport results around the charge neutrality point (CNP) in a type-II InAs/GaSb field-effect transistor. At zero magnetic field, a conductance minimum close to 4e(2)/h develops at the CNP and it follows semi-logarithmic temperature dependence. In quantized magnetic (B) fields and at low temperatures, well developed integer quantum Hall states are observed in the electron as well as hole regimes. Charged carrier (electron and hole) transport shows noisy behavior around the CNP at extremely high B fields. When the diagonal conductivity sigma(xx) is plotted against the Hall conductivity sigma(xy), an unexpected conductivity circle law is observed. (C) 2013 American Institute of Physics. [http://dx.doi.org/10.1063/1.4789555]},
   author = {W Pan and J F Klem and J K Kim and M Thalakulam and M J Cich and S K Lyo},
   issue = {3},
   journal = {Appl Phys Lett},
   keywords = {topological insulators
hall insulator
hybridization
transition
graphene
systems
liquid
well},
   pages = {33504},
   title = {Chaotic quantum transport near the charge neutrality point in inverted type-II InAs/GaSb field-effect transistors},
   volume = {102},
   year = {2013}
}
@article{Park2013,
   abstract = {The Rashba spin-orbit interaction effective field is always in the plane of the two-dimensional electron gas and perpendicular to the carrier wavevector but the direction of the Dresselhaus field depends on the crystal orientation. These two spin-orbit interaction parameters can be determined separately by measuring and analyzing the Shubnikov-de Haas oscillations for various crystal directions. In the InAs quantum well system investigated, the Dresselhaus term is just 5% of the Rashba term. The gate dependence of the oscillation patterns clearly shows that only the Rashba term is modulated by an external electric field. (C) 2013 AIP Publishing LLC.},
   author = {Y H Park and H J Kim and J Chang and S H Han and J Eom and H J Choi and H C Koo},
   issue = {25},
   journal = {Appl Phys Lett},
   keywords = {quantum-wells
heterostructures
transistor
layers},
   pages = {252407},
   title = {Separation of Rashba and Dresselhaus spin-orbit interactions using crystal direction dependent transport measurements},
   volume = {103},
   year = {2013}
}
@article{Patrashin2017,
   abstract = {We report on the growth and characterization of strained-layer InAs/Ga1-xInxSb superlattices for long-wavelength photodetectors. The thickness and alloy composition x < 0.4 of the layers were designed to produce narrow superlattice energy gaps of < 50 meV for optical absorption in the terahertz spectral range. The structures were grown on GaSb (100) substrates by solid-source molecular beam epitaxy. The structure and surface quality were analyzed by using X-ray diffraction, scanning transmission electron microscopy, energy-dispersive spectroscopy, and Rutherford backscattering spectroscopy. Transmittance and reflectance spectra were measured to evaluate the optical properties. The characterization results demonstrated the feasibility of the pseudomorphic growth of strained InAs/GaInSb superlattices and their promising optical properties for long-wavelength photodetectors. (C) 2017 Elsevier B.V. All rights reserved.},
   author = {M Patrashin and K Akahane and N Sekine and I Hosako},
   journal = {J Cryst Growth},
   keywords = {molecular beam epitaxy
superlattices
antimonides
heterojunction semiconducting devices
characterization
x-ray diffraction
semiconductors
gasb
inas},
   pages = {86-90},
   title = {Molecular beam epitaxy of strained-layer InAs/GaInSb superlattices for long-wavelength photodetectors},
   volume = {477},
   year = {2017}
}
@article{Patrashin2011,
   abstract = {We designed InAs/Ga0.6In0.4Sb superlattice (SL) material for terahertz-range photodetectors. Depending on the thicknesses of the InAs and Ga0.6In0.4Sb layers, the SL energy gap E-g can be adjusted to be between 8-25 meV, which corresponds to a cut-off frequency from 2 to 6 THz. Different designs were numerically evaluated by using the eight-band k.p model. The calculations show that the SL energy gap is sensitive to monolayer (ML) scale variations in layer thickness, and that realization of the design parameters requires better than 1ML accuracy of epitaxial growth.
A 40-period strained InAs/Ga0.6In0.4Sb SL with alternating InSb (1ML) and GaAs (1ML) interfaces was grown by a molecular beam epitaxy on a GaSb substrate; the target energy gap E-g was 9 meV. The SL samples were characterized by X-ray diffraction (XRD), atomic force microscopy (AFM), photoluminescence and absorption spectroscopy measurements. Despite the large lattice mismatch between InAs and Ga0.6In0.4Sb, the XRD and AFM measurements showed that the SL had good structural and surface quality and an accurate layer structure. The surface roughness was 0.22 nm.},
   author = {M Patrashin and I Hosako and K Akahane},
   journal = {Millimetre Wave and Terahertz Sensors and Technology Iv},
   keywords = {inas/gainsb superlattice
semiconductor nanostructures
thz sensors
thz imaging systems
quantum-well photodetector
infrared detectors
technology},
   title = {Type-II InAs/GaInSb superlattices for terahertz range photodetectors},
   volume = {8188},
   year = {2011}
}
@article{Petchsingh2007,
   abstract = {Cyclotron resonance measurements are performed as a function of temperature on InAs/GaSb quantum well structures. The effects of electron-hole hybridization on cyclotron resonance are found to be strongly temperature dependent. As the temperature increases, the cyclotron resonance spectra narrow dramatically and multiple splittings due to electron-hole hybridizations disappear. This phenomenon is believed to be due to the classical Coulomb interaction between electrons with different cyclotron effective masses. The influence of the minigap formed due to electron-hole coupling is shown to be particularly important in narrower gap structures where strong thermal excitation of carriers is observed across the minigap. The influence of the minigap on the system is confirmed by the application of large parallel magnetic fields which decouple the electron and hole bands.},
   author = {C Petchsingh and R J Nicholas and K Takashina and N J Mason},
   issue = {3},
   journal = {Semicond Sci Tech},
   keywords = {quantum-wells
inversion-layer
gap heterostructures
magnetic-fields
band overlap
si
superlattices
oscillations
mass
heterojunctions},
   pages = {194-202},
   title = {Temperature-dependent cyclotron resonance in a hybridized electron-hole system in InAs/GaSb heterostructures},
   volume = {22},
   year = {2007}
}
@article{Petchsingh2002,
   abstract = {We report a study of cyclotron resonance (CR) in a bilayer-bipolar InAs/GaSb structure and the influence of the spatial separation between the electrons and holes. At low magnetic fields we find that the cyclotron mass of the electrons can double when the electrons and holes have a very small separation. At higher cyclotron energies we find that the CR lines are split by a series of resonances which are due to interband coupling, and which also increase rapidly in magnitude when the electron-hole separation is decreased. At very high fields, in the quantum limit a new series of couplings is observed, with the resonances being split by energies in the range of 3-12 meV. (C) 2002 Elsevier Science B.V. All rights reserved.},
   author = {C Petchsingh and R J Nicholas and K Takashina and N J Mason and J Zeman},
   issue = {1-4},
   journal = {Physica E-Low-Dimensional Systems and Nanostructures},
   keywords = {inas/gasb
cyclotron resonance
bilayer
effective mass
quantum-wells
heterostructures
hybridization
systems
gap},
   pages = {289-292},
   title = {Mass enhancement and electron-hole coupling in InAs/GaSb bilayers studied by cyclotron resonance},
   volume = {12},
   year = {2002}
}
@article{Petchsingh2004,
   abstract = {The effect of electron-hole hybridization on the cyclotron resonance of bipolar InAs/GaSb structures is investigated for samples with varying electron-hole coupling. At low magnetic fields it is found that the cyclotron resonance mass of the electrons is significantly enhanced when the electrons and holes are closer together and strongly coupled. A two-band model including electron-hole mixing shows excellent agreement with the experimental results. At higher magnetic fields it is observed that the electron cyclotron resonance line is split into a series of resonances due to electron-hole Landau level hybridization. The magnetic-field positions of these splittings are proportional to the energy separation between the electrons and holes, proving the explanation that they are the result of single-particle coupling. In the quantum limit strong couplings and giant spin splitting of the cyclotron resonance transitions are seen which depend strongly on the exact structure studied.},
   author = {C Petchsingh and R J Nicholas and K Takashina and N J Mason and J Zeman},
   issue = {15},
   journal = {Phys Rev B},
   keywords = {al)as heterojunctions
magnetic-fields
conduction-band
ground-state
nonparabolicity
superlattices
systems,in-situ characterization
quantum-wells
effective-mass
gaas-(ga},
   pages = {155306},
   title = {Effects of electron-hole hybridization on cyclotron resonance in InAs/GaSb heterostructures},
   volume = {70},
   year = {2004}
}
@article{Pikulin2014,
   author = {D I Pikulin and T Hyart and S Mi and J Tworzydlo and M Wimmer and C W J Beenakker},
   issue = {19},
   journal = {Phys Rev B},
   pages = {161403},
   title = {Disorder and magnetic-field-induced breakdown of helical edge conduction in an inverted electron-hole bilayer},
   volume = {89},
   year = {2014}
}
@article{Plis2015,
   abstract = {We report on the design, growth, fabrication and characterization of dual-band (long-/long-wave infrared) type-II InAs/GaSb strained layer superlattice (T2SL) detectors with pBp architecture. Under operating the bias of -200 mV and +100 mV, quantum efficiencies of 37% (similar to 11 mu m band) and 25% (similar to 9 mu m band) were realized, respectively. To reduce the dark current in a dual-band T2SL detector, the effect of a "restoration" chemical etch treatment and ZnTe passivation on device performance were investigated. (C) 2014 Elsevier B.V. All rights reserved.},
   author = {E Plis and S Myers and D Ramirez and E P Smith and D Rhiger and C Chen and J D Phillips and S Krishna},
   journal = {Infrared Physics and Technology},
   keywords = {molecular beam epitaxy
infrared detectors
super lattice
pbp detector
dual-band detector
focal-plane arrays
cutoff wavelength
mu-m
photodiodes
passivation},
   pages = {93-98},
   title = {Dual color longwave InAs/GaSb type-II strained layer superlattice detectors},
   volume = {70},
   year = {2015}
}
@article{Prange1981,
   author = {R E Prange},
   issue = {9},
   journal = {Phys Rev B},
   pages = {4802-4805},
   title = {Quantized Hall Resistance and the Measurement of the Fine-Structure Constant},
   volume = {23},
   year = {1981}
}
@article{Pribiag2015,
   abstract = {Topological superconductivity is an exotic state of matter that supports Majorana zero-modes, which have been predicted to occur in the surface states of three-dimensional systems, in the edge states of two-dimensional systems, and in onedimensional wires(1,2). Localized Majorana zero-modes obey non-Abelian exchange statistics, making them interesting building blocks for topological quantum computing(3,4). Here, we report superconductivity induced in the edge modes of semiconducting InAs/GaSb quantum wells, a two-dimensional topological insulator(5-10). Using superconducting quantum interference we demonstrate gate-tuning between edge-dominated and bulk-dominated regimes of superconducting transport. The edge-dominated regime arises only under conditions of high-bulk resistivity, which we associate with the two-dimensional topological phase. These experiments establish InAs/GaSb as a promising platform for the confinement of Majoranas into localized states, enabling future investigations of non-Abelian statistics.},
   author = {V S Pribiag and A J A Beukman and F Qu and M C Cassidy and C Charpentier and W Wegscheider and L P Kouwenhoven},
   issue = {7},
   journal = {Nat Nanotechnol},
   keywords = {hgte quantum-wells
majorana fermions
inas},
   pages = {593-597},
   title = {Edge-mode superconductivity in a two-dimensional topological insulator},
   volume = {10},
   year = {2015}
}
@article{Pryor2005,
   abstract = {We have calculated band-edge energies for most combinations of zinc blende AlN, GaN, InN, GaP, GaAs, InP, InAs, GaSb, and InSb in which one material is strained to the other. Calculations were done for three different geometries (quantum wells, wires, and dots) and mean effective masses were computed in order to estimate confinement energies. For quantum wells, we have also calculated band-edges for ternary alloys. Energy gaps, including confinement, may be easily and accurately estimated using band energies and a simple effective mass approximation, yielding excellent agreement with experimental results. By calculating all material combinations we have identified interesting material combinations, such as artificial donors, that have not been experimentally realized. The calculations were perfomed using strain-dependent k center dot p theory and provide a comprehensive overview of band structures for strained heterostructures.},
   author = {C E Pryor and M E Pistol},
   issue = {20},
   journal = {Phys Rev B},
   keywords = {gasb super-lattices
electronic-structure
semimetal transition
optical-properties
photoluminescence
insb
inp},
   title = {Band-edge diagrams for strained III-V semiconductor quantum wells, wires, and dots},
   volume = {72},
   year = {2005}
}
@article{Qi2006,
   abstract = {We propose models of two-dimensional paramagnetic semiconductors where the intrinsic spin Hall effect is exactly quantized in integer units of a topological charge. The model describes a topological insulator in the bulk and a "holographic metal" at the edge, where the number of extended edge states crossing the Fermi level is dictated by (exactly equal to) the bulk topological charge. We also demonstrate the spin Hall effect explicitly in terms of the spin accumulation caused by the adiabatic flux insertion.},
   author = {X L Qi and Y S Wu and S C Zhang},
   issue = {8},
   journal = {Phys Rev B},
   keywords = {landau-levels
edge states
conductance
model},
   title = {Topological quantization of the spin Hall effect in two-dimensional paramagnetic semiconductors},
   volume = {74},
   year = {2006}
}
@article{Qi2010,
   author = {X L Qi and S C Zhang},
   issue = {1},
   journal = {Phys Today},
   keywords = {single dirac cone
surface
bi2te3
wells
phase},
   pages = {33-38},
   title = {The quantum spin Hall effect and topological insulators},
   volume = {63},
   year = {2010}
}
@article{Quinn1996,
   abstract = {In a heterostructure consisting of neighboring layers of InAs and GaSb in a large band-gap host like AlSb, the bottom of the InAs conduction band lies similar to 150 meV below the top of the GaSb valence band, However, because the electron and hole subbands are weakly coupled for non-zero values of the wavevector k(1) along the layer, an anticrossing of the levels occurs at k(1) =k(c), where k(c)(2) = (2 mu/h(2)) (Delta l-epsilon(0)(v)-epsilon(0)(c)) Herz Delta is the band overlap, epsilon(0)(c) and epsilon(0)(v) are the lowest electron and hole subband energies, and mu is the reduced mass. The splitting is in the order of 5-10 meV. For an intrinsic material, the Fermi level lies in this gap, so that no semimetallic state occurs. If the InAs layers are sufficiently wide, or if an electric field can be applied across the heterostructure (by fabricating front and back gates) it is possible to have the first excited electron subband EP realize an anticrossing with epsilon(o)(v) as well. Then a true semimetallic state can occur with a circle of electrons in the epsilon(1)(c) subband near k(1) = 0, and a ring of holes near the anticrossing in the hybridized valence subband. A semimetal-to-semiconductor transition should occur, which is driven by shifting the single-particle subband energies with an applied electric or magnetic field.},
   author = {J J Quinn and J J Quinn},
   issue = {1-3},
   journal = {Surf Sci},
   keywords = {antimony
arsenic
gallium
gallium selenide
indium
indium arsenide
quantum effects
quantum wells
semiconductor-semiconductor heterostructures
semi-empirical models and model calculations},
   pages = {930-932},
   title = {Semimetal-semiconductor transition in InAs-GaSb heterostructures},
   volume = {361},
   year = {1996}
}
@article{Qu2015,
   abstract = {Among the theoretically predicted two-dimensional topological insulators, InAs/GaSb double quantum wells (DQWs) have a unique double-layered structure with electron and hole gases separated in two layers, which enables tuning of the band alignment via electric and magnetic fields. However, the rich trivial-topological phase diagram has yet to be experimentally explored. We present an in situ and continuous tuning between the trivial and topological insulating phases in InAs/GaSb DQWs through electrical dual gating. Furthermore, we show that an in-plane magnetic field shifts the electron and hole bands relatively to each other in momentum space, functioning as a powerful tool to discriminate between the topologically distinct states.},
   author = {F M Qu and A J A Beukman and S Nadj-Perge and M Wimmer and B M Nguyen and W Yi and J Thorp and M Sokolich and A A Kiselev and M J Manfra and C M Marcus and L P Kouwenhoven},
   issue = {3},
   journal = {Phys Rev Lett},
   keywords = {band-structure
magnetotransport
hybridization
transition},
   pages = {36803},
   title = {Electric and Magnetic Tuning Between the Trivial and Topological Phases in InAs/GaSb Double Quantum Wells},
   volume = {115},
   year = {2015}
}
@article{Reich1995,
   abstract = {Strained layer InAs/GaInSb superlattices have been shown to have many desirable optical and transport properties. The piezoelectric field along the (111) orientation causes a tilting of the energy bands, leading to novel opto-electronic applications. We have carried out the growth of these superlattices on (111) on- and off-axis GaSb substrates. A wide range of growth conditions has been investigated, and high-quality superlattices are demonstrated in a narrow temperature and flux range, as monitored by reflection high-energy electron diffraction (RHEED) reconstruction and post-growth X-ray diffraction analysis.},
   author = {D A Reich and A M Wowchak and P P Chow and J M Vanhove},
   issue = {1-4},
   journal = {J Cryst Growth},
   keywords = {infrared detectors
morphology
interface},
   pages = {849-852},
   title = {(111)Inas/Gainsb Strained-Layer Superlattice Growth Investigation},
   volume = {150},
   year = {1995}
}
@article{Ridley1982,
   author = {B K Ridley},
   issue = {28},
   journal = {J Phys C Solid State},
   pages = {5899-5917},
   title = {The Electron Phonon Interaction in Quasi-2-Dimensional Semiconductor Quantum-Well Structures},
   volume = {15},
   year = {1982}
}
@article{Rod2015,
   abstract = {We study the spin texture of a generic helical liquid, the edge modes of a two-dimensional topological insulator with broken axial spin symmetry. By considering honeycomb and square-lattice realizations of topological insulators, we show that in all cases the generic behavior of a momentum-dependent rotation of the spin quantization axis is realized. Here we establish this mechanism also for disk geometries with continuous rotational symmetry. Finally, we demonstrate that the rotation of spin-quantization axis remains intact for arbitrary geometries, i.e., in the absence of any continuous symmetry. We also calculate the dependence of this rotation on the model and material parameters. Finally, we propose a spectroscopy measurement which should directly reveal the rotation of the spin-quantization axis of the helical edge states.},
   author = {A Rod and T L Schmidt and S Rachel},
   issue = {24},
   journal = {Phys Rev B},
   keywords = {hgte quantum-wells
topological insulators
hall},
   pages = {245112},
   title = {Spin texture of generic helical edge states},
   volume = {91},
   year = {2015}
}
@article{Rogalski2005,
   abstract = {Hitherto, two families of multielement detectors have been used for infrared applications; scanning systems (first generation) and staring systems (second generation). Third generation systems are being developed nowadays. In the common understanding, third generation IR systems provide enhanced capabilities like larger number of pixels, higher frame rates, better thermal resolution as well as multicolour functionality and other on-chip functions.
In the class of third generation infrared photon detectors, two main competitors, HgCdTe photodiodes and AlGaAs/GaAs quantum well infrared photoconductors (QWIPs) are considered. However, in the long wavelength infrared (LWIR) region, the HgCdTe material fail to give the requirements of large format two-dimensional (2D) arrays due to metallurgical problems of the epitaxial layers such as uniformity and number of defected elements.
A superlattice based InAs/GaInSb system grown on GaSb substrate seems to be an attractive to HgCdTe with good spatial uniformity and an ability to span cutoff wavelength from 3 to 25 mu m. The recently published results have indicated that high performance middle wavelength infrared (MWIR) InAs/GaInSb superlatice focal plane arrays can be fabricated. Based on these very promising results it is obvious now that the antimonide superlattice technology is competing with HgCdTe dual colour technology with the potential advantage of standard Ill-V technology to be more competitive in costs and as a consequence series production pricing.},
   author = {A Rogalski},
   journal = {P Soc Photo-Opt Ins},
   keywords = {inas/gainsb superlattices
third generation infrared detectors
focal plane arrays
photodiodes
r(0)a product nedt
minority-carrier lifetimes
inas/inxga1-xsb superlattices
temperature limits
photodiodes
photodetectors
detectivities
imagers},
   pages = {1-12},
   title = {InAs/GaInSb superlattices as a promising material system for third generation infrared detectors},
   volume = {5834},
   year = {2005}
}
@article{Rogalski2006,
   abstract = {Hitherto, two families of multielement detectors have been used for infrared applications: scanning systems (first generation) and staring systems (second generation). Third generation systems are being developed nowadays. In the common understanding, third generation IR systems provide enhanced capabilities like larger number of pixels, higher frame rates, better thermal resolution as well as multicolour functionality and other on-chip functions. In the class of third generation infrared photon detectors, two main competitors, HgCdTe photodiodes and AlGaAs/GaAs quantum well infrared photoconductors (QWIPs) are considered. However, in the long wavelength infrared (LWIR) region, the HgCdTe material fail to give the requirements of large format two-dimensional (2-D) arrays due to metallurgical problems of the epitaxial layers such as uniformity and number of defective elements. A superlattice based InAs/GaInSb system grown on GaSb substrate seems to be an attractive alternative to HgCdTe with good spatial uniformity and an ability to span cut-off wavelength from 3 to 25 pm. The recently published results have indicated that high performance middle wavelength infrared (MWIR) InAs/GaInSb superlattice focal plane arrays can be fabricated. Also LWIR photodiodes with the R(0)A values exceeding 100 Omega cm(2) even with a cut-off wavelength of 14 pm can be achieved. Based on these very promising results it is obvious now that the antimonide SUperlattice technology is competing with HgCdTe dual colour technology with the potential advantage of standard III-V technology to be more competitive in costs and as a consequence series production pricing. (c) 2005 Elsevier B.V. All rights reserved.},
   author = {A Rogalski and P Martyniuk},
   issue = {1},
   journal = {Infrared Phys Techn},
   keywords = {inas/gainsb superlattices
third generation infrared detectors
focal plane arrays
photodiodes
r(0)a product
nedt
minority-carrier lifetimes
inas/inxga1-xsb superlattices
temperature limits
photodetectors
photodiodes
detectivities
performance
imagers},
   pages = {39-52},
   title = {InAs/GaInSb superlattices as a promising material system for third generation infrared detectors},
   volume = {48},
   year = {2006}
}
@article{Romano2017,
   abstract = {Chiral and helical domain walls are generic defects of topological spin-triplet superconductors. We study theoretically the magnetic and transport properties of superconducting singlet-triplet-singlet heterostructure as a function of the phase difference between the singlet leads in the presence of chiral and helical domains inside the spin-triplet region. The local inversion symmetry breaking at the singlet-triplet interface allows the emergence of a static phase-controlled magnetization and generally yields both spin and charge currents flowing along the edges. The parity of the domain wall number affects the relative orientation of the interface moments and currents, while in some cases the domain walls themselves contribute to spin and charge transport. We demonstrate that singlet-triplet heterostructures are a generic prototype to generate and control nondissipative spin and charge effects, putting them in a broader class of systems exhibiting spin-Hall, anomalous Hall effects and similar phenomena. Features of the electron transport and magnetic effects at the interfaces can be employed to assess the presence of domains in chiral/helical superconductors.},
   author = {A Romano and C Noce and I Vekhter and M Cuoco},
   issue = {5},
   journal = {Phys Rev B},
   keywords = {topological insulators
states
surface
sr2ruo4},
   title = {Interface currents and magnetization in singlet-triplet superconducting heterostructures: Role of chiral and helical domains},
   volume = {96},
   year = {2017}
}
@book{Rosenberg1988,
   author = {H M Rosenberg},
   edition = {3rd},
   publisher = {Oxford University Press},
   title = {The solid state : an introduction to the physics of crystals for students of physics, materials science and engineering},
   year = {1988}
}
@book{,
   author = {Fausto Rossi},
   keywords = {Semiconductors.
Quantum dots.},
   pages = {319 pages},
   title = {Semiconductor macroatoms : basic physics and quantum-device applications}
}
@article{Rothe2010,
   abstract = {Using k.p theory, we derive an effective four-band model describing the physics of the typical two-dimensional topological insulator (HgTe/CdTe quantum well (QW)) in the presence of an out-of-plane (in the z-direction) inversion breaking potential and an in-plane potential. We find that up to third order in perturbation theory, only the inversion breaking potential generates new elements to the four-band Hamiltonian that are off-diagonal in spin space. When this new effective Hamiltonian is folded into an effective two-band model for the conduction (electron) or valence (heavy hole) bands, two competing terms appear: (i) a Rashba spin-orbit interaction originating from inversion breaking potential in the z-direction and (ii) an in-plane Pauli term as a consequence of the in-plane potential. Spin transport in the conduction band is further analysed within the Landauer-Buttiker formalism. We find that for asymmetrically doped HgTe QWs, the behaviour of the spin-Hall conductance is dominated by the Rashba term.},
   author = {D G Rothe and R W Reinthaler and C X Liu and L W Molenkamp and S C Zhang and E M Hankiewicz},
   journal = {New J Phys},
   keywords = {state},
   pages = {65012},
   title = {Fingerprint of different spin-orbit terms for spin transport in HgTe quantum wells},
   volume = {12},
   year = {2010}
}
@article{Roussignol1992,
   abstract = {We present a study of spin relaxation of excitons in a set of nominally undoped GaAs/AlGaAs quantum well (QW) structures by using time-resolved photoluminescence techniques.  The initial polarization and the spin relaxation time have been measured varying the excitation energy between the heavy- and light-hole exciton of each well, at a temperature of 4 K.  Typical spin relaxation times in the 50-120 ps range are found when increasing the well width from 25 to 90 angstrom; however no dependence of the spin relaxation time on the excitation wavelength has been observed.},
   author = {P Roussignol and P Rolland and R Ferreira and C Delalande and G Bastard and A Vinattieri and L Carraresi and M Colocci and B Etienne},
   issue = {1-3},
   journal = {Surf Sci},
   keywords = {relaxation
luminescence},
   pages = {360-364},
   title = {Time-Resolved Spin-Polarization Spectroscopy in GaAs/AlGaAs Quantum-Wells},
   volume = {267},
   year = {1992}
}
@article{Rudy1973,
   author = {E Rudy},
   issue = {2},
   journal = {J Less-Common Met},
   pages = {245-273},
   title = {Constitution of Ternary Titanium-Tungsten-Carbon Alloys},
   volume = {33},
   year = {1973}
}
@article{Ryczko2015,
   abstract = {In this paper, we present theoretical investigation of the band structure properties of the type-II W-design AlSb/InAs/GaInSb/InAs/AlSb quantum wells predicted for the active region of interband cascade lasers emitting in a broad range of mid infrared. We utilize the multiband k.p theory in order to calculate the dependence of the energy and oscillator strength of the fundamental optical transition on the thickness of particular layers confining electrons and holes, including the external bias to simulate the conditions occurring in an operational device. It is shown that for a given electric field the properly chosen thicknesses of the wells allow optimizing simultaneously the emission wavelength and type II transition intensity for any wavelength up to about 12 mu m at least.(C) 2014 Elsevier Ltd. All rights reserved.},
   author = {K Ryczko and T Liszka},
   journal = {Superlattice Microst},
   keywords = {ii-type quantum well
mid infrared
interband cascade lasers
semiconductors},
   pages = {144-149},
   title = {Tailoring the effect of electric field in type II W-design InAs/GaInSb quantum well structures for emission up to 12 mu m},
   volume = {78},
   year = {2015}
}
@article{Samaraweera2018,
   abstract = {A small and narrow negative-magnetoresistance (MR) effect that appears about null magnetic field over the interval -0.025 <= B <= 0.025 T in magnetotransport studies of the GaAs/AlGaAs 2D system with mu approximate to 10(7)cm(2)/Vs is experimentally examined as a function of the sample temperature, T. The temperature dependent magnetoresistance data were fit using the Hikami et al. theory, without including the spinorbit correction, to extract the inelastic length, l(i), which decreases rapidly with increasing temperature. It turns out that l(i) < l(e), where l(e) is the elastic length, for all T. Thus, we measured the single particle lifetime, tau(s), and the single particle mean free path l(s) = upsilon(F)tau(s). A comparison between l(i) and l(s) indicates that l(i) > l(s). The results suggest that the observed small and narrow magnetoresistance effect about null magnetic field could be a manifestation of coherent backscattering due to small angle scattering from remote ionized donors in the high mobility GaAs/AlGaAs 2DES.},
   author = {R L Samaraweera and H C Liu and B Gunawardana and A Kriisa and C Reichl and W Wegscheider and R G Mani},
   journal = {Sci Rep-Uk},
   keywords = {zero-resistance states
electromagnetic-wave excitation
weak-localization
scattering times
magnetoresistance
heterostructures
radiation
films
gaas
oscillations},
   pages = {10061},
   title = {Coherent backscattering in quasi-ballistic ultra-high mobility GaAs/AlGaAs 2DES},
   volume = {8},
   year = {2018}
}
@article{Paulo2002,
   abstract = {We propose a general method for describing tapping-mode atomic-force microscopy. The combined participation of attractive and repulsive interactions determines the multivalued nature of the resonance curve. This, in turn, implies the coexistence of two different stable oscillations for some excitation frequencies. The coexistence of two stable oscillations depends on the driving force and tip-surface separation. Increasing the driving force inhibits the low-amplitude oscillation state. Because resolution depends on the oscillation state, we propose that the absence of the low amplitude solution is responsible for the inconsistencies observed in high-resolution imaging of biomolecules.},
   author = {A San Paulo and R Garcia},
   issue = {4},
   journal = {Phys Rev B},
   keywords = {sample interaction regimes
intermittent contact
tip
phase
contrast
dynamics
kinetics
surface
system
scale},
   pages = {41406},
   title = {Unifying theory of tapping-mode atomic-force microscopy},
   volume = {66},
   year = {2002}
}
@article{Sandhu2001,
   abstract = {The decay of spin memory in a 2D electron gas is found to be suppressed close to the metal-insulator transition. By dynamically probing the device using ultrafast spectroscopy, relaxation of optically excited electron spin is directly measured as a function of the carrier density. Motional narrowing favors spin preservation in the maximally scattered but nonlocalized electronic states. This implies that the spin-relaxation rate can be both tuned in situ and specifically engineered in appropriate device geometries.},
   author = {J S Sandhu and A P Heberle and J J Baumberg and J R A Cleaver},
   issue = {10},
   journal = {Phys Rev Lett},
   keywords = {metal-insulator-transition
quantum-wells
heterostructures
gaas
injection
spectroscopy
polarization
transport
dynamics},
   pages = {2150-2153},
   title = {Gateable suppression of spin relaxation in semiconductors},
   volume = {86},
   year = {2001}
}
@article{Schliemann2003,
   abstract = {We propose a spin-field-effect transistor based on spin-orbit coupling of both the Rashba and the Dresselhaus types. Different from earlier proposals, spin transport through our device is tolerant against spin-independent scattering processes. Hence the requirement of strictly ballistic transport can be relaxed. This follows from a unique interplay between the Dresselhaus and the Rashba coupling; these can be tuned to have equal strengths, leading to k-independent eigenspinors even in two dimensions. We discuss two-dimensional devices as well as quantum wires. In the latter, our setup presents strictly parabolic dispersions which avoids complications from anticrossings of different bands.},
   author = {J Schliemann and J C Egues and D Loss},
   issue = {14},
   journal = {Phys Rev Lett},
   keywords = {2-dimensional electron-gas
orbit interaction
quantum-wells
conduction-band
heterostructures
relaxation
precession
scattering
transport
systems},
   pages = {146801},
   title = {Nonballistic spin-field-effect transistor},
   volume = {90},
   year = {2003}
}
@article{Schmidt2012,
   abstract = {We evaluate the low-temperature conductance of a weakly interacting one-dimensional helical liquid without axial spin symmetry. The lack of that symmetry allows for inelastic backscattering of a single electron, accompanied by forward scattering of another. This joint effect of weak interactions and potential scattering off impurities results in a temperature-dependent deviation from the quantized conductance, delta G proportional to T-4. In addition, delta G is sensitive to the position of the Fermi level. We determine numerically the parameters entering our generic model for the Bernevig-Hughes-Zhang Hamiltonian of a HgTe/CdTe quantum well in the presence of Rashba spin-orbit coupling.},
   author = {T L Schmidt and S Rachel and F von Oppen and L I Glazman},
   issue = {15},
   journal = {Phys Rev Lett},
   keywords = {hgte quantum-wells},
   title = {Inelastic Electron Backscattering in a Generic Helical Edge Channel},
   volume = {108},
   year = {2012}
}
@article{Segal1981,
   author = {H R Segal and T A Dewinter and Z J J Stekly and K Hemachalam},
   issue = {1},
   journal = {Ieee T Magn},
   pages = {53-56},
   title = {The Use of NbTiTa as a High-Field Superconducting Alloy},
   volume = {17},
   year = {1981}
}
@article{Sela1991,
   abstract = {We present a Raman scattering study of the InAs/GaInSb superlattice.  This new superlattice is promising as a long wavelength infrared detector material.  The samples were grown by molecular beam epitaxy and their structural parameters were determined by Rutherford backscattering and x-ray diffraction.  Samples were grown on [001] GaAs substrates with GaSb buffers, and directly on [001] GaSb substrates.  Cross-sectional transmission electron micrographs show that for the samples grown on GaAs substrates, a high density of dislocations was generated at the GaAs-GaSb interface, and many of these dislocations thread through the superlattice.  The samples grown directly on GaSb had a much lower dislocation density.  The Raman spectra of the InAs/GaInSb superlattice shows a single peak, which is a superposition of scattering from the LO phonons in InAs and in GaInSb.  For unstrained InAs and GaInSb, the LO phonon energies are sufficiently separated that they would be well resolved in Raman scattering.  However, the strain introduced into these materials by the pseudomorphic boundary conditions moves the two phonons closer together energetically so that only one peak is seen in the Raman spectrum of the superlattice.  A high energy Raman scattering tail is seen in some of the samples.  This tail is from Ga-As local modes.  Such modes may be due to As incorporation in the GaInSb, Ga incorporation in the InAs or phase mixing at the interfaces.},
   author = {I Sela and I H Campbell and B K Laurich and D L Smith and L A Samoska and C R Bolognesi and A C Gossard and H Kroemer},
   issue = {10},
   journal = {J Appl Phys},
   keywords = {infrared detectors
gasb
inas
interface
gap},
   pages = {5608-5614},
   title = {Raman-Scattering Study of Inas/Gainsb Strained Layer Superlattices},
   volume = {70},
   year = {1991}
}
@article{Shi2015,
   abstract = {We report on strong transport anisotropy in a two-dimensional hole gas in a Ge/SiGe quantum well, which emerges only when both perpendicular and in-plane magnetic fields are present. The ratio of resistances, measured along and perpendicular to the in-plane field, can exceed 3 x 10(4). The anisotropy occurs in a wide range of filling factors where it is determined primarily by the tilt angle. The lack of significant anisotropy without an in-plane field, easy tunability, and persistence to higher temperatures and filling factors set this anisotropy apart from nematic phases in GaAs/AlGaAs.},
   author = {Q Shi and M A Zudov and C Morrison and M Myronov},
   issue = {20},
   journal = {Phys Rev B},
   keywords = {high landau-levels
2-dimensional electron liquid
charge-density-wave
state
magnetoresistance
systems
phase},
   pages = {201301},
   title = {Strong transport anisotropy in Ge/SiGe quantum wells in tilted magnetic fields},
   volume = {91},
   year = {2015}
}
@article{Shojaei2018,
   abstract = {In an ideal InAs/GaSb bilayer of appropriate dimension, in-plane electron and hole bands overlap and hybridize, and a topologically nontrivial, or quantum spin Hall (QSH) insulator, phase is predicted to exist. The in-plane dispersion's potential landscape, however, is subject to microscopic perturbations originating from material imperfections. In this work, the effect of disorder on the electronic structure of InAs/GaSb (001) bilayers was studied by observing the temperature and magnetic-field dependence of the resistance of a dual-gated heterostructure gate-tuned through the inverted to normal gap regimes. Conduction with the electronic structure tuned to the inverted (predicted topological) regime and the Fermi level in the hybridization gap was qualitatively similar to behavior in a disordered two-dimensional system. The impact of charged impurities and interface roughness on the formation of topologically protected edge states and an insulating bulk was estimated. The experimental evidence and estimates of disorder in the potential landscape indicated that the potential fluctuations in state-of-the-art films are sufficiently strong such that conduction with the electronic structure tuned to the predicted topological insulator (TI) regime and the Fermi level in the hybridization gap was dominated by a symplectic metal phase rather than a TI phase. The implications are that future efforts must address disorder in this system, and focus must be placed on the reduction of defects and disorder in these heterostructures if a TI regime is to be achieved.},
   author = {B Shojaei and A P McFadden and M Pendharkar and J S Lee and M E Flatte and C J Palmstrom},
   issue = {6},
   journal = {Phys Rev Mater},
   keywords = {quantum-wells
band-structure
superlattices
hybridization},
   pages = {64603},
   title = {Materials considerations for forming the topological insulator phase in InAs/GaSb heterostructures},
   volume = {2},
   year = {2018}
}
@article{Shojaei2016,
   abstract = {Control of zero-field spin splitting is realized in a dual-gated high-quality InAs-AlSb two-dimensional electron gas. Magnetotransport experiments showed clean Shubnikov-de Haas oscillations down to low magnetic fields, and the gate-tuned electron mobility exceeded 700 000 cm(2)/Vs. A clear beating effect was observed in magnetoresistance oscillations at large potential asymmetry between gates. Beat patterns due to zero-field spin splitting and other classes of transverse magnetoresistance oscillations were distinguished by temperature-dependent magnetoresistance measurements. Analysis of the magnetoresistance oscillations indicated that the zero-field spin splitting could be tuned via the Rashba effect while keeping the two-dimensional electron gas charge density constant.},
   author = {B Shojaei and P J J O'Malley and J Shabani and P Roushan and B D Schultz and R M Lutchyn and C Nayak and J M Martinis and C J Palmstrom},
   issue = {7},
   journal = {Phys Rev B},
   keywords = {quantum-wells
orbit interaction
band parameters
oscillations
heterostructures
semiconductors
conductivity
spintronics
scattering
interface},
   title = {Demonstration of gate control of spin splitting in a high-mobility InAs/AlSb two-dimensional electron gas},
   volume = {93},
   year = {2016}
}
@article{Shvartsman2008,
   abstract = {We suggest to use InAs/GaSb coupled quantum wells for terahertz lasing. In these heterostructures terahertz lasing is based not on intersubband but on interband transitions. Crucial advantages of this design in comparison with intersubband lasers are (i) a large value of the interband dipole matrix element and (ii) easier maintenance of population inversion. These advantages lead to a gain of two orders of magnitude higher than that for intersubband lasing. Even higher gain can be obtained in special design InAs/GaSb W-structures where a hybridization gap of 1-3 THz is formed and optical density of states is singular. (C) 2008 American Institute of Physics.},
   author = {L D Shvartsman and B Laikhtman},
   issue = {13},
   journal = {Appl Phys Lett},
   keywords = {quantum-wells},
   pages = {131104},
   title = {InAs-GaSb laser: Prospects for efficient terahertz emission},
   volume = {93},
   year = {2008}
}
@article{Siggia1970,
   author = {E D Siggia and P C Kwok},
   issue = {4},
   journal = {Phys Rev B},
   pages = {1024-1036},
   title = {Properties of Electrons in Semiconductor Inversion Layers with Many Occupied Electric Subbands .1. Screening and Impurity Scattering},
   volume = {2},
   year = {1970}
}
@article{Spanton2014,
   abstract = {Quantum spin Hall devices with edges much longer than several microns do not display ballistic transport; that is, their measured conductances are much less than e(2)/h per edge. We imaged edge currents in InAs/GaSb quantum wells with long edges and determined an effective edge resistance. Surprisingly, although the effective edge resistance is much greater than h/e(2), it is independent of temperature up to 30 K within experimental resolution. Known candidate scattering mechanisms do not explain our observation of an effective edge resistance that is large yet temperature independent.},
   author = {E M Spanton and K C Nowack and L J Du and G Sullivan and R R Du and K A Moler},
   issue = {2},
   journal = {Phys Rev Lett},
   keywords = {state},
   pages = {26804},
   title = {Images of Edge Current in InAs/GaSb Quantum Wells},
   volume = {113},
   year = {2014}
}
@article{Stadelmann2002,
   abstract = {Magnetotransport measurements have been performed in strongly coupled two-dimensional electron-hole gases in an InAs Gash heterostructure in the presence of antidot potentials of different strengths. We have observed commensurability features in the magnetoresistance that we attribute to high mobility electrons. It is proposed that they can be observed due to magnetic breakdown, despite the fact that the electron-hole mixing is found to play an important role. (C) 2002 Elsevier Science B.V. All rights reserved.},
   author = {T O Stadelmann and B Kardynal and R J Nicholas and K Takashima and N J Mason},
   issue = {1-4},
   journal = {Physica E},
   keywords = {magnetoresistance
lateral superlattices
magnetoresistance},
   pages = {293-295},
   title = {Magnetotransport studies of antidot superlattices in coupled two-dimensional electron-hole gases},
   volume = {12},
   year = {2002}
}
@article{Stern1983,
   author = {F Stern},
   issue = {14},
   journal = {Current Contents/Physical Chemical and Earth Sciences},
   pages = {22},
   title = {Properties of Semiconductor Surface Inversion-Layers in the Electric Quantum Limit},
   year = {1983}
}
@article{Stormer1982,
   author = {H L Stormer and A C Gossard and W Wiegmann},
   issue = {10},
   journal = {Solid State Commun},
   pages = {707-709},
   title = {Observation of Intersubband Scattering in a Two-Dimensional Electron-System},
   volume = {41},
   year = {1982}
}
@misc{STROMBERG1965,
   author = {Thorsten Frederick STROMBERG},
   institution = {Iowa State University of Science and Technology},
   title = {The Superconducting Properties of High Purity Niobium},
   year = {1965}
}
@article{Suchalkin2003,
   abstract = {Optical gain and loss have been measured in type II InAs/GaInSb interband cascade lasers operating in the 3.4-3.6 mum wavelength range. The maximum temperature of cw operation was found to be limited by strong gain saturation due to active region overheating, while the temperature increase of the total optical loss was relatively small. In devices with a longer lasing wavelength and a thinner substrate-side cladding layer, a strong periodic modulation of the optical gain spectra was observed. This effect is consistent with resonant optical leakage into the substrate. (C) 2003 American Institute of Physics.},
   author = {S Suchalkin and J Bruno and R Tober and D Westerfeld and M Kisin and G Belenky},
   issue = {8},
   journal = {Appl Phys Lett},
   keywords = {power},
   pages = {1500-1502},
   title = {Experimental study of the optical gain and loss in InAs/GaInSb interband cascade lasers},
   volume = {83},
   year = {2003}
}
@article{Sundaram1992,
   abstract = {Cyclotron resonance measurements are reported for both electrons and holes in type II InAs/GaSb superlattices and double heterostructures (DHETS). Superlattice (multi quantum well) samples of InAs/GaSb grown by MOVPE have sufficiently high hole gas mobilities and densities to allow the first measurements of hole cyclotron resonance in this system. The measured hole masses are approximately 0.1m(e) and 0.2 m(e), indicating a large reduction over the bulk values due to the decoupling of the valence band by strain and confinement. This is in good agreement with eight-band k . p theory reported here, and previous calculations. The electron masses in both superlattices and DHETs are found to be strongly influenced by non-parabolicity and the carrier concentration, leading to considerable increases over the band edge values. Similar values are found for both electron and hole masses in structures grown along both [001] and [111]A directions.},
   author = {G M Sundaram and R J Warburton and R J Nicholas and G M Summers and N J Mason and P J Walker},
   issue = {7},
   journal = {Semicond Sci Tech},
   keywords = {two-dimensional holes
gasb super-lattices
quantum-wells
landau-levels
layer
superlattices
heterojunctions
dependence
subbands
fields},
   pages = {985-993},
   title = {Cyclotron-Resonance in InAs/GaSb Heterostructures},
   volume = {7},
   year = {1992}
}
@article{Suzuki2015,
   abstract = {We report a gate-controlled transition of a semimetallic InAs/GaSb heterostructure to a topological insulator. The transition is induced by decreasing the degree of band inversion with front- and back-gate voltages. Temperature dependence of the longitudinal resistance peak shows the energy gap opening in the bulk region with increasing gate electric field. The suppression of bulk conduction and the transition to a topological insulator are confirmed by nonlocal resistance measurements using a dual lock-in technique, which allows us to rigorously compare the voltage distribution in the sample for different current paths without the influence of time-dependent resistance fluctuations.},
   author = {K Suzuki and Y Harada and K Onomitsu and K Muraki},
   issue = {24},
   journal = {Phys Rev B},
   keywords = {hgte quantum-wells
hybridization
state},
   pages = {245309},
   title = {Gate-controlled semimetal-topological insulator transition in an InAs/GaSb heterostructure},
   volume = {91},
   year = {2015}
}
@article{Suzuki2003,
   abstract = {Transport properties in asymmetric InAs/GaSb and InAs/AlSb/GaSb heterostructures sandwiched by AlGaSb layers were studied. For the InAs/GaSb structures, partially compensated quantum Hall effects arising from the electron-hole hybridization were observed. By changing the thickness of each layer, the energy positions of the conduction band and the valence band can be controlled independently. In InAs/AlSb/GaSb structures, we tried to control the hybridization strength by varying the AlSb barrier thickness. Magnetoresistance measurements, in which the magnetic field was applied perpendicular and parallel to the surface, and cyclotron resonance (CR) measurements show that there is a clear transition from the electron-hole-hybridized system to the electron-hole-independent system. The transition point appeared at around the 2-nm-barrier thickness in all experiments, suggesting a dominant role of the overlap of electron and hole wave functions. According to the absorption peak shapes in the CR measurements, the hybridized system can be further classified as strongly hybridized or weakly hybridized. Only in the weakly hybridized system was the Shubnikov-de Haas-like oscillation due to the short-range scattering by the hole potential observed in the electron CR absorption peak.},
   author = {K Suzuki and S Miyashita and Y Hirayama},
   issue = {19},
   journal = {Phys Rev B},
   keywords = {quantum-wells
gap heterostructures
cyclotron-resonance
ground-state
layers},
   pages = {195319},
   title = {Transport properties in asymmetric InAs/AlSb/GaSb electron-hole hybridized systems},
   volume = {67},
   year = {2003}
}
@article{Suzuki2004,
   abstract = {The quantum Hall effect in electron-hole hybridized systems is examined using back-gated InAs/(AlSb)/GaSb heterostructures with different electron-hole coupling. When the electrons and holes are strongly coupled, it is found that quantized Hall states appear when the net filling factor [nu(net)=(n-p)h/eB, where n and p are the electron and hole densities, respectively] is an integer, and that it is not a necessary condition for independent electron and hole filling factors (nu(e)=nh/eB and nu(h)=ph/eB) to be integers simultaneously. The observed phenomena can be interpreted in terms of a simple model where the Landau-level fans associated with the electrons and holes hybridize resulting in an effective band gap at nu(net)=0, and the quantized Hall states occur according to the number of hybridized Landau levels occupied above this gap.},
   author = {K Suzuki and K Takashina and S Miyashita and Y Hirayama},
   issue = {1},
   journal = {Phys Rev Lett},
   keywords = {heterostructures
transition},
   pages = {16803},
   title = {Landau-level hybridization and the quantum Hall effect in InAs/(AlSb)/GaSb electron-hole systems},
   volume = {93},
   year = {2004}
}
@article{Symons1994,
   abstract = {Magnetotransport measurements have been carried out under hydrostatic pressure on [001]- and [111]-oriented InAs/GaSb structures grown by metal-organic vapor-phase epitaxy. The system is semimetallic at zero pressure, but as the pressure is increased, electrons, located in the InAs layers, transfer back into the valence band of GaSb and a semimetal-to-semiconductor transition is observed. In double heterojunctions the zero band overlap condition occurs at 14 and 17 kbar for the [001] and [111]A orientations, respectively. The band crossing at the interface has been calculated self-consistently for the two orientations, taking into account the intrinsic and extrinsic origins of the carriers. This band overlap is found not only to be strongly orientation dependent, approximately 60 meV larger in [111]A compared with [001], but also to decrease at rates of 10 and 12 meV/kbar for the [001] and [111]A orientations, respectively. These rates are much larger than those determined from molecular beam epitaxy samples, but closer to the variation with pressure of the band gaps of the bulk materials.},
   author = {D M Symons and M Lakrimi and R J Warburton and R J Nicholas and N J Mason and P J Walker and M I Eremets and G Hill},
   issue = {23},
   journal = {Phys Rev B},
   keywords = {inas-gasb heterostructures
magnetic-field
quantum wells
hole gas
superlattices
heterojunctions
interface
gasb/inas
growth
movpe},
   pages = {16614-16621},
   title = {[001]-Oriented and Piezoelectric-[111]-Oriented Inas/Gasb Structures under Hydrostatic-Pressure},
   volume = {49},
   year = {1994}
}
@article{Tahamtan2011,
   abstract = {The electrical and structural properties of AuGeNi ohmic contact to n-GaAs have been studied. A combination of EDX and X-ray diffraction analysis was used to examine the reactions between AuGeNi-based metallization and GaAs. Scanning Tunneling Microscope (STM) was used to study surface morphology and surface roughness. By the use of Rapid Thermal Annealing (RTA), contact resistivity as low as 5.5 x 10(-8) Omega cm(2) have been obtained. The minimum in the contact resistivity coincides with the formation of AuGa and NiAs phases. On the other hand, poor thermal stability after contact formation was concluded to be due to the formation of low melting point AuGa phases. Formation of dark particles, recognized as GeNi particles, in different distributions and shapes after annealing, was found to be essential for low contact resistivity. Correlation between GeNi particles distribution and contact resistivity was found and introduced as d/lambda parameter. It was found that the lower the size of these particles (d) as well as the larger the contact area over which they are distributed (lambda) leading to the better contact resistivity. (C) 2011 Elsevier Ltd. All rights reserved.},
   author = {S Tahamtan and A Goodarzi and S P Abbasi and A Hodaei and M S Zabihi and J Sabbaghzadeh},
   issue = {8},
   journal = {Microelectron Reliab},
   keywords = {interfacial microstructure
ingaas},
   pages = {1330-1336},
   title = {Investigation on the effect of annealing process parameters on AuGeNi ohmic contact to n-GaAs using microstructural characteristics},
   volume = {51},
   year = {2011}
}
@article{Takagaki2016,
   abstract = {Quantum interference in scattering from a potential offset is investigated in narrow strips of two-dimensional systems described by the Bernevig-Hughes-Zhang Hamiltonian. Attention is focused on the situations where the transmission in the scattering region takes place around the Dirac point of topological insulators when the hybridization energy gap is eliminated by utilizing transverse interference. Apart from conventional periodic transmission modulation that takes place when the length of the potential offset region is varied, resonant disappearances of reflection occur for short potential offsets. The anomalous resonance appears not only for the four-band Hamiltonian but also for the two-band Hamiltonian, manifesting the generality of the phenomenon. Evanescent-like waves excited around the potential steps are indicated to be responsible for the anomalous behavior. The interference states can couple with each other and generic reduction in the amplitude of transmission modulation occurs upon coupling with the periodic modulation. Published by AIP Publishing.},
   author = {Y Takagaki},
   issue = {12},
   journal = {J Appl Phys},
   keywords = {klein paradox
edge states
graphene
wells},
   title = {Quantum interference by localized scattering waves of gapless helical modes in narrow strips of topological insulators},
   volume = {120},
   year = {2016}
}
@article{Tang2012,
   abstract = {In this paper, we present two key process steps for potential applications in the fabrication of low-cost and high-efficiency ultrathin monocrystalline silicon (mono-Si) solar cells to effectively harvest solar energy. One is to grow an Al2O3 passivation layer on the rear side of an Si wafer by a successive atomic layer deposition (ALD) at room temperature (25 degrees C). The other is to produce a bio-inspired antireflection structure on the front side of the Si wafer by replicating butterfly wing patterns. The capacitance-voltage measurements reveal that the successive ALD procedure can yield a higher negative charge density at the Al2O3/Si interface relative to the conventional one. The measurement results of quasi-steady-state photoconductance indicate that after annealing, the 25 degrees C ALD Al2O3 layers reach a similar passivation level to the p-type Si wafers compared to that deposited at 250 degrees C. With the help of an ALD Al2O3 layer, butterfly wing patterns (Hypochrysops polycletus) are replicated on a PMMA layer which is on an SiO2/Si stack. This work demonstrates the ability for replicating the natural photonic features on Si wafers and other substrates by using nanoimprint. (C) 2012 American Vacuum Society. [DOI: 10.1116/1.3669521]},
   author = {X Tang and L A Francis and P Simonis and M Haslinger and R Delamare and O Deschaume and D Flandre and P Defrance and A M Jonas and J P Vigneron and J P Raskin},
   issue = {1},
   journal = {Journal of Vacuum Science and Technology A},
   keywords = {optical-absorption
solar-cells
silicon
arrays},
   title = {Room temperature atomic layer deposition of Al_2O_3 and replication of butterfly wings for photovoltaic application},
   volume = {30},
   year = {2012}
}
@article{Thouless1982,
   author = {D J Thouless and M Kohmoto and M P Nightingale and M Dennijs},
   issue = {6},
   journal = {Phys Rev Lett},
   pages = {405-408},
   title = {Quantized Hall Conductance in a Two-Dimensional Periodic Potential},
   volume = {49},
   year = {1982}
}
@article{Tian2014,
   abstract = {Weak antilocalization (WAL) and linear magnetoresistance (LMR) are two most commonly observed magnetoresistance (MR) phenomena in topological insulators (TIs) and often attributed to the Dirac topological surface states (TSS). However, ambiguities exist because these phenomena could also come from bulk states (often carrying significant conduction in many TIs) and are observable even in non-TI materials. Here, we demonstrate back-gated ambipolar TI field-effect transistors in (Bi0.04Sb0.96)(2)Te-3 thin films grown by molecular beam epitaxy on SrTiO3(111), exhibiting a large carrier density tunability (by nearly 2 orders of magnitude) and a metal-insulator transition in the bulk (allowing switching off the bulk conduction). Tuning the Fermi level from bulk band to TSS strongly enhances both the WAL (increasing the number of quantum coherent channels from one to peak around two) and LMR (increasing its slope by up to 10 times). The SS-enhanced LMR is accompanied by a strongly nonlinear Hall effect, suggesting important roles of charge inhomogeneity (and a related classical LMR), although existing models of LMR cannot capture all aspects of our data. Our systematic gate and temperature dependent magnetotransport studies provide deeper insights into the nature of both MR phenomena and reveal differences between bulk and TSS transport in TI related materials.},
   author = {J F Tian and C Z Chang and H L Cao and K He and X C Ma and Q K Xue and Y P Chen},
   journal = {Sci Rep-Uk},
   keywords = {single dirac cone
linear magnetoresistance
weak antilocalization
bi2se3
bi2te3
oscillations
nanoribbons
transport
graphene
srtio3},
   title = {Quantum and Classical Magnetoresistance in Ambipolar Topological Insulator Transistors with Gate-tunable Bulk and Surface Conduction},
   volume = {4},
   year = {2014}
}
@article{Tiemann2017,
   abstract = {Electron-hole hybridization in InAs/GaSb double quantum well structures leads to the formation of a miniband- gap. We experimentally and theoretically studied the impact of strain on the transport properties of this material system. Thinned samples were mounted to piezoelectric elements to exert strain along the [011] and [001] crystal directions. When the Fermi energy is tuned through the minigap, the resistivity at the charge neutrality point is found to be susceptible to external strain. In the electron and hole regimes, strain influences the Landau level structure. By analyzing the intrinsic strain from the epitaxial growth and the external strain from the piezo elements and combining our experimental results with numerical simulations of strained and unstrained quantum wells, we can illustrate why the InAs/GaSb material system is regularly found to be semimetallic.},
   author = {L Tiemann and S Mueller and Q S Wu and T Tschirky and K Ensslin and W Wegscheider and M Troyer and A A Soluyanov and T Ihn},
   issue = {11},
   journal = {Phys Rev B},
   keywords = {semimetal-semiconductor transition
augmented-wave method
heterostructures
gasb
inas
alsb},
   pages = {115108},
   title = {Impact of strain on the electronic properties of InAs/GaSb quantum well systems},
   volume = {95},
   year = {2017}
}
@article{Tkachov2013,
   abstract = {In a topological insulator (TI) the character of electron transport varies from insulating in the interior of the material to metallic near its surface. Unlike, however, ordinary metals, conducting surface states in TIs are topologically protected and characterized by spin helicity whereby the direction of the electron spin is locked to the momentum direction. In this paper we review selected topics regarding recent theoretical and experimental work on electron transport and related phenomena in two-dimensional (2D) and three-dimensional (3D) TIs. The review provides a focused introductory discussion of the quantum spin Hall effect in HgTe quantum wells as well as transport properties of 3DTIs such as surface weak antilocalization, the half-integer quantum Hall effect, s+p-wave induced superconductivity, superconducting Klein tunneling, topological Andreev bound states and related Majorana midgap states. These properties of TIs are of practical interest, guiding the search for the routes towards topological spin electronics.},
   author = {G Tkachov and E M Hankiewicz},
   issue = {2},
   journal = {Phys Status Solidi B},
   keywords = {josephson effect
proximity effect
quantum spin hall effect
topological insulators
hgte quantum-wells
single dirac cone
weak antilocalization
thin-films
wave superconductors
orbit interaction
phase-transition
magnetic-field
edge states
hall state},
   pages = {215-232},
   title = {Spin-helical transport in normal and superconducting topological insulators},
   volume = {250},
   year = {2013}
}
@article{Tong2017,
   abstract = {We have experimentally studied the persistent photoconductivity (PPC) in inverted InAs/GaSb and InAs/GaInSb quantum wells, which can be tuned into a bulk-insulating state by electron-hole hybridization. Specifically we tune the bulk band structure and carriers with light-emitting diode (LED) illuminations. The persistent photoconductivity could be negative or positive, depending on the specific doping structure and the illuminating photon energy. Compared to the widely-used electrostatically gating method, our findings provide a more flexible and non-invasive way to control the band structures and charge states in InAs/GaSb and InAs/GaInSb quantum wells (QWs). (C) 2017 Author(s).},
   author = {B B Tong and Z D Han and T X Li and C Zhang and G Sullivan and R R Du},
   issue = {7},
   journal = {Aip Adv},
   keywords = {heterostructures},
   title = {Tuning the charge states in InAs/GaSb or InAs/GaInSb composite quantum wells by persistent photoconductivity},
   volume = {7},
   year = {2017}
}
@book{Tsao1993,
   author = {Jeffrey Y Tsao},
   keywords = {Molecular beam epitaxy.
Surfaces (Physics)
Surfaces (Technology)},
   pages = {xxi, 301 p},
   publisher = {Academic Press},
   title = {Materials fundamentals of molecular beam epitaxy},
   year = {1993}
}
@article{Tschirky2017,
   abstract = {We study molecular beam epitaxially grown undoped Al chi Ga1-xSb/InAs/AlSb quantum wells with different buffer and barrier designs and varying quantum well width. The highest mobilities were achieved with Al0.33Ga0.67Sb buffers and lower barriers and a quantum well width of 24 nm. These quasi-single- interface InAs/AlSb quantum well devices reached a gate-tuned mobility of 2.4 x 10(6) cm(2)/V s at a density of 1 x 10(12) cm(-2) and 1.3 K. In Hall bar devices boundary scattering is found to strongly influence the mobility determination in this mobility regime. Ionized background impurity scattering at low electron densities, device boundary scattering at intermediate electron densities, and intersubband scattering at high electron densities were identified as the most likely dominant scattering processes. Ringlike structures in the Landau fan can be explained using a single- particle model of crossing Landau levels.},
   author = {T Tschirky and S Mueller and C A Lehner and S Falt and T Ihn and K Ensslin and W Wegscheider},
   issue = {11},
   journal = {Phys Rev B},
   keywords = {2-dimensional electron-gas
interface roughness scattering
heterostructures
transport
semiconductors
spintronics
relaxation
gaas
time},
   pages = {115304},
   title = {Scattering mechanisms of highest-mobility InAs/Al_xGa_(1-x)Sb quantum wells},
   volume = {95},
   year = {2017}
}
@article{Tuttle1990,
   author = {G Tuttle and H Kroemer and J H English},
   issue = {6},
   journal = {J Appl Phys},
   pages = {3032-3037},
   title = {Effects of Interface Layer Sequencing on the Transport-Properties of InAs/AlSb Quantum-Wells - Evidence for Antisite Donors at the InAs/AlSb Interface},
   volume = {67},
   year = {1990}
}
@article{vanHall1989,
   author = {P J van Hall},
   issue = {2},
   journal = {Superlattice Microst},
   pages = {213-216},
   title = {Remote Impurity Scattering in GaAs-AlGaAs Heterojunctions},
   volume = {6},
   year = {1989}
}
@article{vanHall1988,
   author = {P J van Hall and T Klaver and J H Wolter},
   issue = {2},
   journal = {Semicond Sci Tech},
   pages = {120-123},
   title = {Remote Impurity Scattering in Heterojunctions},
   volume = {3},
   year = {1988}
}
@article{VanvechtJa1969,
   author = {Vanvecht.Ja},
   issue = {3},
   journal = {B Am Phys Soc},
   pages = {317-&},
   title = {Quantum Dielectric Theory of Electronegativity in Covalent Systems .I. Electronic Dielectric Constant},
   volume = {14},
   year = {1969}
}
@article{VanvechtJa1969,
   author = {Vanvecht.Ja},
   issue = {3},
   journal = {B Am Phys Soc},
   pages = {317-&},
   title = {Quantum Dielectric Theory of Electronegativity in Covalent Systems .I. Electronic Dielectric Constant},
   volume = {14},
   year = {1969}
}
@article{Vanvechten1969,
   author = {J A Vanvechten},
   issue = {3},
   journal = {Phys Rev},
   pages = {891-903},
   title = {Quantum Dielectric Theory of Electronegativity in Covalent Systems .I. Electronic Dielectric Constant},
   volume = {182},
   year = {1969}
}
@article{Vasilyev1999,
   abstract = {Cyclotron-resonance (CR) experiments have been performed on InAs/GaSb/AlSb double structures, in which electron and hole layers are separated by AlSb barriers. The strength of the electron-hole coupling is altered by varying the barrier width. Our data reveal that properties of InAs/GaSb systems with AlSb barriers thinner than 1.5 nm are entirely determined by interlayer tunneling and the CR features in such samples can be explained by hybridization between states in the InAs conduction band and in the GaSb valence band. [S0163-1829(99)14235-8].},
   author = {Y Vasilyev and S Suchalkin and K von Klitzing and B Meltser and S Ivanov and P Kop'ev},
   issue = {15},
   journal = {Phys Rev B},
   keywords = {inas quantum-wells
gasb
superlattices
oscillations
systems},
   pages = {10636-10639},
   title = {Evidence for electron-hole hybridization in cyclotron-resonance spectra of InAs/GaSb heterostructures},
   volume = {60},
   year = {1999}
}
@article{Vonklitzing1980,
   author = {K Vonklitzing and G Dorda and M Pepper},
   issue = {6},
   journal = {Phys Rev Lett},
   pages = {494-497},
   title = {New Method for High-Accuracy Determination of the Fine-Structure Constant Based on Quantized Hall Resistance},
   volume = {45},
   year = {1980}
}
@article{deVries2017,
   author = {Arjan J A Beukman.
Folkert K de Vries. and Jasper van Veen. and Rafal Skolasinski. and Michael Wimmer.},
   issue = {24},
   journal = {Phys Rev B},
   title = {Spin-orbit interaction in a dual gated InAs/GaSb quantum well},
   volume = {96},
   year = {2017}
}
@article{Vurgaftman2001,
   abstract = {We present a comprehensive, up-to-date compilation of band parameters for the technologically important III-V zinc blende and wurtzite compound semiconductors: GaAs, GaSb, GaP, GaN, AlAs, AlSb, AlP, AlN, InAs, InSb, InP, and InN, along with their ternary and quaternary alloys. Based on a review of the existing literature, complete and consistent parameter sets are given for all materials. Emphasizing the quantities required for band structure calculations, we tabulate the direct and indirect energy gaps, spin-orbit, and crystal-field splittings, alloy bowing parameters, effective masses for electrons, heavy, light, and split-off holes, Luttinger parameters, interband momentum matrix elements, and deformation potentials, including temperature and alloy-composition dependences where available. Heterostructure band offsets are also given, on an absolute scale that allows any material to be aligned relative to any other. (C) 2001 American Institute of Physics.},
   author = {I Vurgaftman and J R Meyer and L R Ram-Mohan},
   issue = {11},
   journal = {J Appl Phys},
   keywords = {molecular-beam-epitaxy
vapor-phase epitaxy
single-quantum-wells
electron effective-mass
ray photoemission spectroscopy
strained-layer superlattices
light-emitting-diodes
first-principles calculations
level transient spectroscopy
direct-energy-gap},
   pages = {5815-5875},
   title = {Band parameters for III-V compound semiconductors and their alloys},
   volume = {89},
   year = {2001}
}
@article{Wang2014,
   abstract = {The quantum anomalous Hall effect has recently been observed experimentally in thin films of Cr-doped (Bi, Sb)(2)Te-3 at a low temperature (similar to 30 mK). In this work, we propose realizing the quantum anomalous Hall effect in more conventional diluted magnetic semiconductors with magnetically doped InAs/GaSb type-II quantum wells. Based on a four-band model, we find an enhancement of the Curie temperature of ferromagnetism due to band edge singularities in the inverted regime of InAs/GaSb quantum wells. Below the Curie temperature, the quantum anomalous Hall effect is confirmed by the direct calculation of Hall conductance. The parameter regime for the quantum anomalous Hall phase is identified based on the eight-band Kane model. The high sample quality and strong exchange coupling make magnetically doped InAs/GaSb quantum wells good candidates for realizing the quantum anomalous Hall insulator at a high temperature.},
   author = {Q Z Wang and X Liu and H J Zhang and N Samarth and S C Zhang and C X Liu},
   issue = {14},
   journal = {Phys Rev Lett},
   keywords = {semiconductor heterostructures
ferromagnetic semiconductors
transition
insulator
model
gap},
   title = {Quantum Anomalous Hall Effect in Magnetically Doped InAs/GaSb Quantum Wells},
   volume = {113},
   year = {2014}
}
@article{Wang2016,
   abstract = {The search for a new quantum spin Hall (QSH) phase and effective manipulation of its edge states are very important for both fundamental sciences and practical applications. Here, we use first-principles calculations to study the strain-driven topological phase transition of two-dimensional (2D) arsenene monolayer. We find that the band gap of arsenene decreases with increasing strain and changes from indirect to direct, and then the s-p band inversion takes place at the. point as the tensile strain is larger than 11.14%, which leads to a nontrivially topological state. A single pair of topologically protected helical edge states is established for the edge of arsenene, and their QSH states are confirmed with the nontrivial topological invariant Z(2) = 1. We also propose high-dielectric BN as an ideal substrate for the experimental synthesis of arsenene, maintaining its nontrivial topology. These findings provide a promising candidate platform for topological phenomena and new quantum devices operating at nanoelectronics.},
   author = {Y P Wang and C W Zhang and W X Ji and R W Zhang and P Li and P J Wang and M J Ren and X L Chen and M Yuan},
   issue = {5},
   journal = {J Phys D Appl Phys},
   keywords = {quantum spin hall effect
arsenene
band inversion
first-principles calculations
topological insulators
phosphorene
wells},
   title = {Tunable quantum spin Hall effect via strain in two-dimensional arsenene monolayer},
   volume = {49},
   year = {2016}
}
@article{Wu2017,
   abstract = {The electronic structure of an inverted InAs/GaSb quantum well embedded in AlSb barriers is studied theoretically. The influence of an in-plane magnetic field is examined within the 14-band k.p approach. The spin-dependent subband energy dispersion curves are strongly modified by the in-plane magnetic field and by the conduction-valence band hybridization. The dispersion curves in the direction parallel to the magnetic field become quite different from that in the perpendicular direction. At strong magnetic fields, one observes the interplay between the confinement induced by the magnetic field and the confinement due to the quantum well, and the interplay between the strong intrinsic spin-orbit interaction and the spin alignment induced by the magnetic field. The well-known two-dimensional topological insulator model is generalized to take into account the influence of the in-plane magnetic field. The bulk-like state conduction channels become available in addition to the edge state conduction channels for a moderate magnetic field. Published by AIP Publishing.},
   author = {X G Wu},
   issue = {22},
   journal = {J Appl Phys},
   keywords = {cyclotron-resonance oscillations
hole system
heterostructures
microstructures
superlattices
hybridization
state
gaas
gap},
   pages = {225704},
   title = {Influence of an in-plane magnetic field on the electronic structure of an inverted InAs/GaSb quantum well},
   volume = {122},
   year = {2017}
}
@article{Weimar1998,
   abstract = {The optical and electrical properties of InAs/GaInSb superlattice mesa photodiodes with a cutoff wavelength around 8 mu m are investigated. The influence of the surface potential at the mesa sidewalls on the device properties was studied by fabricating gate-controlled diodes. At least two mechanisms determining the dark current in the reverse bias region can be identified. At high reverse biases bulk band-to-band tunneling dominates while the current at low reverse biases is most likely governed by surface effects. Bulk interband tunneling is further investigated by applying magnetic fields B up to 7 T parallel and perpendicular to the electric field E across the p-n junction.},
   author = {U Weimar and F Fuchs and E Ahlswede and J Schmitz and W Pletschen and N Herres and M Walther},
   journal = {Mater Res Soc Symp P},
   pages = {123-128},
   title = {Tunneling effects in InAs/GaInSb superlattice infrared photodiodes},
   volume = {484},
   year = {1998}
}
@article{X2016,
   author = {Xiao X. and Y Liu and Z Liu and G Ai and S Yang and G Zhou},
   issue = {2},
   journal = {Appl Phys Lett},
   title = {All-electric spin modulator based on a two-dimensional topological insulator},
   volume = {108},
   year = {2016}
}
@article{Xia1992,
   abstract = {We study theoretically the magnetoexcitons in a GaSb-AlSb-InAs quantum-well structure. Two numerical approaches, a variational and an expansion method, have been proposed to study the exciton ground state. The exciton binding energy has been found to increase with increasing applied magnetic field and with decreasing layer thicknesses of the GaSb, AlSb, and InAs materials. The strength of the applied magnetic field, along with quantum-well structure parameters, determines the condition under which the system undergoes transition from semiconductor to excitonic phase. The excited states of the magnetoexcitons have also been studied with the application of the expansion method.},
   author = {X Xia and X M Chen and J J Quinn},
   issue = {11},
   journal = {Phys Rev B},
   keywords = {exciton binding-energy
electron
hole},
   pages = {7212-7215},
   title = {Magnetoexcitons in a GaSb-Alsb-InAs Quantum-Well Structure},
   volume = {46},
   year = {1992}
}
@article{Xu2010,
   abstract = {We present a detailed theoretical study on the features of band hybridization and zero-field spin-splitting in InAs/AlSb/GaSb quantum wells (QWs). An eight-band k . p approach is developed to calculate the electronic subband structure in such structures. In the absence of the AlSb layer, the hybridized energy gaps can be observed at the anticrossing points between the lowest electron subband and the highest heavy-hole subband in the InAs and GaSb layers respectively. In such a case, the position and magnitude of the gaps are spin-dependent. When a thin AlSb layer is inserted between the InAs and GaSb layers, we find that the lowest electron subband in the InAs layer is only hybridized with the highest light-hole subband which is also hybridized with the highest heavy-hole subband in the GaSb layer. The hybridized energy gaps and spin-splitting in the InAs/AlSb/GaSb QWs are reduced significantly. These results can be used to understand why electrons and holes can be well separated and why relatively high mobilities for electrons and holes can be achieved in InAs/AlSb/GaSb type II and broken-gap QWs. The present study is relevant to the applications of InAs/GaSb based QW structures as new generation of high-density and high-mobility electronic devices. (C) 2010 American Institute of Physics. [doi :10.1063/1.3476059]},
   author = {W Xu and L L Li and H M Dong and G Gumbs and P A Folkes},
   issue = {5},
   journal = {J Appl Phys},
   keywords = {envelope-function approximation
semiconductor superlattices
electronic-structure
heterostructures
hole},
   pages = {53709},
   title = {Band hybridization and spin-splitting in InAs/AlSb/GaSb type II and broken-gap quantum wells},
   volume = {108},
   year = {2010}
}
@article{Yang1998,
   abstract = {We proposed and demonstrated a new type of quantum cascade laser based on interband transitions in InAs/GaInSb/AlSb type-II quantum wells. Contrary to the conventional heterostructure or quantum well lasers, this device takes advantage of recycling carriers from valence band back to conduction band for sequential photon emissions to achieve high quantum efficiency. So far, an external differential quantum efficiency exceeding 200% has been observed from 4-mu m lasers under 1 mu s pulses and 0.1% duty cycle at 80 K. Under 5-10 mu s pulse lengths and 10% duty cycle, peak powers >160 mW have been obtained, the corresponding internal quantum efficiency was deduced to be 220%.},
   author = {B H Yang and R Q Yang and D Zhang and C H Lin and S S Pei},
   journal = {Semiconductor Lasers Iii},
   keywords = {semiconductor lasers
mid-infrared
type-ii structure
quantum efficiency
molecular beam epitaxy},
   pages = {324-332},
   title = {High quantum efficiency InAs/GaInSb/AlSb interband cascade lasers},
   volume = {3547},
   year = {1998}
}
@article{Yang1997,
   abstract = {InAs/GaSb composite quantum wells sandwiched by AlSb are studied by using capacitance-voltage, quantum Hall, and three-terminal transfer measurements. Our data reveal a positive energy gap resulting from the hybridization of in-plane dispersions of electrons in InAs and holes in GaSb for conventionally recognized ''semimetallic'' InAs/GaSb heterostructures.},
   author = {M J Yang and C H Yang and B R Bennett and B V Shanabrook},
   issue = {24},
   journal = {Phys Rev Lett},
   keywords = {band-structure
quantum wells
gasb
transition
states},
   pages = {4613-4616},
   title = {Evidence of a hybridization gap in ``semimetallic'' InAs/GaSb systems},
   volume = {78},
   year = {1997}
}
@article{Yevtushenko2015,
   abstract = {We study the edge transport in two-dimensional topological insulators which is carried by interacting helical fermions. This transport is ballistic when it is protected by time-reversal symmetry. Recently it was pointed out (ALTSHULER B. L. et al., Phys. Rev. Lett., 111 (2013) 086401) that coupling of non-interacting helical electrons to an array of randomly anisotropic magnetic (Kondo) impurities can lead to a spontaneous breaking of the symmetry and, thus, can remove this protection. By using a combination of the functional and the Abelian bosonization approaches, we show that the suppression of the ballistic transport turns out to be robust in a broad range of the interaction strength. We have evaluated the renormalization of the localization length and have found that, for strong interaction, it is substantial. We have identified various regimes of the dc transport and discussed its temperature and sample size dependences in each of the regimes. Copyright (C) EPLA, 2015},
   author = {O M Yevtushenko and A Wugalter and V I Yudson and B L Altshuler},
   issue = {5},
   journal = {Epl-Europhys Lett},
   keywords = {hgte quantum-wells
topological insulators
transition
states},
   title = {Transport in helical Luttinger liquid with Kondo impurities},
   volume = {112},
   year = {2015}
}
@article{Ying1995,
   abstract = {Direct determination of subband densities via measurements of Shubnikov-de Haas oscillations in coupled bilayer electron systems reveals a many-body-induced interlayer charge transfer as the front layer is depleted by a front-gate bias: with decreasing front-gate bias the back-layer electron density increases while the front-layer density decreases faster than linearly. The data are in excellent quantitative agreement with a self-consistent calculation that includes exchange and correlation energies via local-density approximation.},
   author = {X Ying and S R Parihar and H C Manoharan and M Shayegan},
   issue = {16},
   journal = {Phys Rev B},
   keywords = {quantum hall state},
   pages = {11611-11614},
   title = {Quantitative-Determination of Many-Body-Induced Interlayer Charge-Transfer in Bilayer Electron-Systems Via Shubnikov-de Haas Measurements},
   volume = {52},
   year = {1995}
}
@article{Yu2016,
   abstract = {The ratio of Rashba and Dresselhaus spin splittings of the (001)-grown GaAs/AlGaAs quantum wells (QWs), investigated by the spin photocurrent spectra induced by circular photogalvanic effect (CPGE) at inter-band excitation, has been effectively tuned by changing the well width of QWs and by inserting a one-monolayer-thick InAs layer at interfaces of GaAs/AlGaAs QWs. Reflectance difference spectroscopy (RDS) is also employed to study the interface asymmetry of the QWs, whose results are in good agreement with that obtained by CPGE measurements. It is demonstrated that the inserted ultra-thin InAs layers will not only introduce structure inversion asymmetry (SIA), but also result in additional interface inversion asymmetry (IIA), whose effect is much stronger in QWs with smaller well width. It is also found that the inserted InAs layer brings in larger SIA than IIA. The origins of the additional SIA and IIA introduced by the inserted ultra-thin InAs layer have been discussed.},
   author = {J L Yu and X L Zeng and S Y Cheng and Y H Chen and Y Liu and Y F Lai and Q Zheng and J Ren},
   journal = {Nanoscale Res Lett},
   keywords = {spectroscopy of circular photogalvanic effect
ratio of rashba/dresselhaus spin splittings
rashba- and dresselhaus-type cpge
interface inversion asymmetry
reflectance difference spectroscopy
band excitation
dependence
asymmetry},
   pages = {477},
   title = {Tuning of Rashba/Dresselhaus Spin Splittings by Inserting Ultra-Thin InAs Layers at Interfaces in Insulating GaAs/AlGaAs Quantum Wells},
   volume = {11},
   year = {2016}
}
@article{Zakharova2001,
   abstract = {We have investigated the hybridization of the electron states. the light-hole states and the heavy-hole states in InAs/GaSb broken-gap quantum wells. This effect is profound Mien the InAs layer and the GaSb layer are sufficiently thick such that the electron level lies below the heavy-hole level and the light-hole level at zone center. To calculate the dispersions and the wave functions in these structures we have applied the scattering matrix algorithm to the eight-band k.p model. We have found a hybridization gap as large as 20 meV resulting from the anticrossing of the electron and the light-hole dispersion curves. A multiple anticrossing of the electron states. the light-hole states and the heavy-hole states may occur when the heavy hole level lies in the hybridization gap produced by the electron states and the light-hole states. This unusual hybridization of the three subbands. which behaves differently for the "spin-up" and the "spin-down" states. has been investigated in details around the anticrossing point, While the electronlike and light holelike states mix strongly, the heavy holelike state may remain unperturbed.},
   author = {A Zakharova and S T Yen and K A Chao},
   issue = {23},
   journal = {Phys Rev B},
   keywords = {broken-gap
superlattices
heterostructures
band
systems},
   pages = {235332},
   title = {Hybridization of electron, light-hole, and heavy-hole states in InAs/GaSb quantum wells},
   volume = {64},
   year = {2001}
}
@article{Zakharova2002,
   abstract = {We investigate the hybridization of the electron, heavy-hole and/or light-hole dispersion relations in strained InAs/GaSb quantum wells. In the considered structures, the lowest electron level lies below several hole levels at zero in-plane wave vector k(parallel to), so that the anticrossings of subbands produce gaps in the in-plane dispersions. To calculate the electronic band structures of such quantum wells grown on different substrates, we use the eight-band k.p model and the scattering matrix method. We have found that the order of levels at the zone center (k(parallel to)=0), gap positions and magnitudes can change due to the lattice-mismatched strain. Strain can also enhance the hybridization of electron and light-hole states at k(parallel to)=0 considerably. In the structure with a thick InAs layer grown on GaSb, we have obtained a negative indirect gap in the in-plane dispersion resulting from the anticrossing of electronlike and highest heavy-hole-like subbands. If the substrate is InAs, the gap becomes direct and positive. This phenomenon can be treated as strain-induced semimetal-semiconductor phase transition.},
   author = {A Zakharova and S T Yen and K A Chao},
   issue = {8},
   journal = {Phys Rev B},
   keywords = {gasb super-lattices
electron-hole hybridization
zincblende crystals
cyclotron-resonance
band-structure
heterostructures
superlattices
systems},
   pages = {85312},
   title = {Strain-induced semimetal-semiconductor transition in InAs/GaSb broken-gap quantum wells},
   volume = {66},
   year = {2002}
}
@article{Zhang2015,
   abstract = {By means of density functional theory (DFT) computations, we predict that the suitable strain modulation of honeycomb arsenene results in a unique two-dimensional (2D) topological insulator (TI) with a sizable bulk gap (up to 696 meV), which could be characterized and utilized at room temperature. Without considering any spin-orbit coupling, the band inversion occurs around the Gamma (G) point at tensile strains larger than 11.7%, which indicates the quantum spin Hall effect in arsenene at appropriate strains. The nontrivial topological phase was further confirmed by the topological invariant nu = 1 and edge states with a single Dirac-type crossing at the G point. Our results provide a promising strategy for designing 2D TIs with large bulk gaps from commonly used materials.},
   author = {H J Zhang and Y D Ma and Z F Chen},
   issue = {45},
   journal = {Nanoscale},
   keywords = {single dirac cone
topological insulators
band-gap
transition
semiconductor
phosphorene
graphene
surface
field},
   pages = {19152-19159},
   title = {Quantum spin Hall insulators in strain-modified arsenene},
   volume = {7},
   year = {2015}
}
@article{Zhang2016,
   abstract = {Quantum spin Hall (QSH) insulators feature edge states that topologically protected from backscattering. However, the major obstacles to application for QSH effect are the lack of suitable QSH insulators with a large bulk gap. Based on first-principles calculations, we predict a class of large-gap QSH insulators in ethynyl-derivative functionalized stanene (SnC2X; X = H, F, Cl, Br, I), allowing for viable applications at room temperature. Noticeably, the SnC2Cl, SnC2Br, and SnC2I are QSH insulators with a bulk gap of similar to 0.2 eV, while the SnC2H and SnC2F can be transformed into QSH insulator under the tensile strains. A single pair of topologically protected helical edge states is established for the edge of these systems with the Dirac point locating at the bulk gap, and their QSH states are confirmed with topological invariant Z(2) = 1. The films on BN substrate also maintain a nontrivial large-gap QSH effect, which harbors a Dirac cone lying within the band gap. These findings may shed new light in future design and fabrication of large-gap QSH insulators based on two-dimensional honeycomb lattices in spintronics.},
   author = {R W Zhang and C W Zhang and W X Ji and S S Li and S S Yan and S J Hu and P Li and P J Wang and F Li},
   journal = {Sci Rep-Uk},
   keywords = {total-energy calculations
wave basis-set
topological insulators
surface
germanane
growth
strain},
   title = {Room Temperature Quantum Spin Hall Insulator in Ethynyl-Derivative Functionalized Stanene Films},
   volume = {6},
   year = {2016}
}
@article{Zhang2000,
   abstract = {Hirsch [Phys. Rev. Lett. 83, 1834 (1999)] recently proposed a spin Hall effect based on the anomalous scattering mechanism in the absence of spin-flip scattering. Since the anomalous scattering causes both anomalous currents and a finite spin-diffusion length, we derive the spin Hall effect in the presence of spin diffusion from a semiclassical Boltzmann equation. When the formulation is applied to certain metals and semiconductors, the magnitude of the spin Hall voltage due to the spin accumulation is found to be much larger than that of magnetic multilayers. An experiment is proposed to measure this spin Hall effect.},
   author = {S F Zhang},
   issue = {2},
   journal = {Phys Rev Lett},
   keywords = {magnetic multilayers
magnetoresistance},
   pages = {393-396},
   title = {Spin Hall effect in the presence of spin diffusion},
   volume = {85},
   year = {2000}
}
@article{Zhang2009,
   abstract = {This work reports a study of the nonlinear Hall effect (HE) in the semimetallic ferromagnet EuB6. A distinct switch in its Hall resistivity slope is observed in the paramagnetic phase, which occurs at a single critical magnetization over a wide temperature range. The observation is interpreted as the point of percolation for entities of a more conducting and magnetically ordered phase in a less ordered background. With an increasing applied magnetic field, the conducting regions either increase in number or expand beyond the percolation limit, hence increasing the global conductivity and effective carrier density. An empirical two-component model provides excellent scaling and a quantitative fit to the HE data and may be applicable to other correlated electron systems.},
   author = {X H Zhang and L Q Yu and S von Molnar and Z Fisk and P Xiong},
   issue = {10},
   journal = {Phys Rev Lett},
   keywords = {fermi-surface
temperature
manganites
magnetoresistance
semiconductors
transition
transport},
   pages = {106602},
   title = {Nonlinear Hall Effect as a Signature of Electronic Phase Separation in the Semimetallic Ferromagnet {EuB$_6$}},
   volume = {103},
   year = {2009}
}
@article{Zhu1990,
   author = {X D Zhu and J J Quinn and G Gumbs},
   issue = {7},
   journal = {Solid State Commun},
   pages = {595-599},
   title = {Excitonic Insulator Transition in a GaSb-AlSb-InAs Quantum-Well Structure},
   volume = {75},
   year = {1990}
}
@article{Fornari2016,
   abstract = {Structural properties of topological insulator bismuth telluride films grown epitaxially on (111) BaF2 with a fixed Bi2Te3 beam flux were systematically investigated as a function of substrate temperature and additional Te flux. A layer-by-layer growth mode is observed since the early stages of epitaxy and remains throughout the whole deposition. Composition of the epitaxial films produced here stays between Bi2Te3 and Bi4Te5, as determined from the comparison of the measured x-ray diffraction curves with calculations. The substrate temperature region, where the growth rate remains constant, is found to be the most appropriate to obtain ordered Bi2Te3 films. Line width of the L = 18 Bi2Te3 diffraction peaks as low as 140 arcsec was obtained, indicating high crystalline quality. Twinning domains density rises with increasing growth temperature and reducing Te extra flux. X-ray reflectivity curves of pure Bi2Te3 films with thickness from 165 to 8 nm exhibited well defined interference fringes, evidencing homogeneous layers with smooth surface. Our results demonstrate that Bi2Te3 films with very well controlled structural parameters can be obtained. High structural quality Bi2Te3 films as thin as only eight quintuple layers grown here are promising candidates for intrinsic topological insulator.},
   author = {Celso I Fornari and Paulo H O Rappl and Sérgio L Morelhão and Eduardo Abramof},
   doi = {10.1063/1.4947266},
   issn = {10897550},
   issue = {16},
   journal = {Journal of Applied Physics},
   month = {10},
   publisher = {American Institute of Physics Inc.},
   title = {Structural properties of Bi2Te3 topological insulator thin films grown by molecular beam epitaxy on (111) BaF2 substrates},
   volume = {119},
   year = {2016}
}
@misc{,
   author = {R R Alfano and United States. National Aeronautics and Space Administration.},
   keywords = {Absorption spectra.
Energy gap (Solid state).
Gallium arsenides.
Indium phosphides.
Photoluminescene.
Quantum wells.
Semiconductors (Materials).
Solar cells.},
   note = {principal investigator, prof. R.R. Alfano.
Shipping list no.: 96-0038-M.
NASA contractor report NASA CR-198945.},
   title = {Investigation of the basic physics of high efficiency semiconductor hot carrier solar cell annual status report for NASA grant #NAG 3-1490}
}
@article{Sarma2013,
   abstract = {We theoretically consider the carrier density dependence of low-temperature electrical conductivity in highquality and low-disorder two-dimensional (2D) "metallic" electronic systems such as 2D GaAs electron or hole quantum wells or doped/gated graphene. Taking into account resistive scattering by Coulomb disorder arising from quenched random charged impurities in the environment, we show that the 2D conductivity sigma(n) varies as sigma similar to n(beta(n)) as a function of the 2D carrier density n where the exponent beta(n) is a smooth, but nonmonotonic, function of density n with possible nontrivial extrema. In particular, the density scaling exponent beta(n) depends qualitatively on whether the Coulomb disorder arises primarily from remote or background charged impurities or short-range disorder and can, in principle, be used to characterize the nature of the dominant background disorder. A specific important prediction of the theory is that for resistive scattering by remote charged impurities, the exponent beta can reach a value as large as 2.7 for k(F)d similar to 1, where k(F) similar to root n is the 2D Fermi wave vector and d is the separation of the remote impurities from the 2D layer. Such an exponent beta (>5/2) is surprising because unscreened Coulomb scattering by remote impurities gives a limiting theoretical scaling exponent of beta = 5/2, and naively one would expect beta(n) <= 5/2 for all densities since unscreened Coulomb scattering should nominally be the situation bounding the resistive scattering from above. We find numerically and show theoretically that the maximum value of alpha (beta), the mobility (conductivity) exponent, for 2D semiconductor quantum wells is around 1.7 (2.7) for all values of d (and for both electrons and holes) with the maximum a occurring around k(F)d similar to 1. We discuss experimental scenarios for the verification of our theory.},
   author = {S Das Sarma and E H Hwang},
   issue = {3},
   journal = {Physical Review B},
   keywords = {metal-insulator-transition
semiconductor quantum-wells
charged-impurity-scattering
silicon inversion-layers
molecular-beam epitaxy
electron-gas
2 dimensions
alxga1-xas/gaas heterojunctions
gaas/algaas heterostructures
residual resistivity},
   note = {188TG
Times Cited:18
Cited References Count:79},
   pages = {35439},
   title = {Universal density scaling of disorder-limited low-temperature conductivity in high-mobility two-dimensional systems},
   volume = {88},
   year = {2013}
}
@article{Sarma1985,
   author = {S Das Sarma and F Stern},
   issue = {12},
   journal = {Physical Review B},
   note = {Awe91
Times Cited:277
Cited References Count:30},
   pages = {8442-8444},
   title = {Single-Particle Relaxation-Time Versus Scattering Time in an Impure Electron-Gas},
   volume = {32},
   year = {1985}
}
@article{de-Leon1999,
   abstract = {We calculate here the energy spectrum of InAs/GaSb heterostructure taking into account a complicated, anisotropic, and nonparabolic structure of the valence band of GaSb. In InAs/GaSb heterostructures the valence band of the GaSb layer overlaps with the conduction band of the InAs layer. The electrons in the Inks layer are coupled to the holes in the GaSb layer and a hybridization gap is formed. The coupling is considered here as a small perturbation for the problem of two decoupled infinite quantum wells, one of holes and one of electrons. The band structure of the coupled system shows features that result from anisotropy, dependence of the coupling on the in-plane vector, and lifting of the double degeneracy of the energy bands of electrons and holes due to the coupling. The splitting of the energy bands is very important at the crossing point. Interesting results of these effects are the possibility of a new kind of a gapless state and nontrivial constant energy contours. [S0163-1829(99)02027-5].},
   author = {S de-Leon and L D Shvartsman and B Laikhtman},
   issue = {3},
   journal = {Physical Review B},
   keywords = {electron-hole system
cyclotron-resonance oscillations
excitonic ground-state
gasb
transition
field
heterostructures
hybridization
superlattices
interfaces},
   note = {218kj
Times Cited:30
Cited References Count:45},
   pages = {1861-1870},
   title = {Band structure of coupled InAs/GaSb quantum wells},
   volume = {60},
   year = {1999}
}
@book{,
   author = {J W Ekin},
   keywords = {Low temperatures Measurement.
Low temperatures Instruments.
Low temperature research.
Superconductors.},
   note = {2006010332
Jack W. Ekin.
illustrations ; 26 cm
Includes bibliographical references and index.},
   pages = {6-704},
   publisher = {Oxford University Press},
   title = {Experimental techniques for low-temperature measurements }
}
@book{,
   abstract = {Modern electronics is being transformed as device size decreases to a size where the dimensions are significantly smaller than the constituent electron's mean free path. In such systems the electron motion is strongly confined resulting in dramatic changes of behaviour compared to the bulk. This book introduces the physics and applications of transport in such mesoscopic and nanoscale electronic systems and devices. The behaviour of these novel devices is influenced by numerous effects not seen in bulk semiconductors, such as the Aharonov-Bohm Effect, disorder and localization, energy quantization, electron wave interference, spin splitting, tunnelling and the quantum hall effect to name a few. Including coverage of recent developments, and with a chapter on carbon-based nanoelectronics, this book will provide a good course text for advanced students or as a handy reference for researchers or those entering this interdisciplinary area.},
   author = {David K Ferry and Institute of Physics (Great Britain)},
   keywords = {Electron transport.
Semiconductors.
Nanostructured materials Electric properties.
Nanostructures Electric properties.
Mesoscopic phenomena (Physics)
Electronic books.},
   note = {10.1088/978-0-7503-1103-8
(OCoLC)919548128
David K. Ferry.
illustrations (some color).
"Version: 20150801"–Title page verso.
Includes bibliographical references.
Preface – Author biography – 1. The world of nanoelectronics – 1.1. Moore's law – 1.2. Nanostructures – 1.3. On the concept of localization – 1.4. Some electronic time and length scales – 1.5. Heterostructures for mesoscopic devices – 1.6. Nanofabrication.
2. Wires and channels – 2.1. The quantum point contact – 2.2. The density of states – 2.3. The Landauer formula – 2.4. Temperature, scattering, and anomalies – 2.5. Beyond the simple theory for the QPC – 2.6. Landauer's contact resistance and scaled CMOS – 2.7. Simulating the channel: the scattering matrix – 2.8. Simulating the channel: the recursive Green's function – Appendix A. Coupled quantum and Poisson problems – Appendix B. The harmonic oscillator – Appendix C. Discretizing the Schr©œdinger equation.
3. The Aharonov-Bohm effect – 3.1. Simple gauge theory of the AB effect – 3.2. Temperature dependence of the AB effect – 3.3. The AB effect in other structures – 3.4. Gated AB rings – 3.5. The electrostatic AB effect – 3.6. The AAS effect – 3.7. Weak localization – Appendix D. The gauge in field theory.
4. Carbon and other new materials – 4.1. Graphene – 4.2. Carbon nanotubes – 4.3. Topological insulators – 4.4. The chalcogenides – Appendix E. Klein tunneling.
5. Localization and fluctuations – 5.1. Localization of electronic states – 5.2. Conductivity – 5.3. Conductance fluctuations – 5.4. Phase-breaking time.
6. The quantum Hall effect – 6.1. The Shubnikov-de Haas effect – 6.2. The quantum Hall effect – 6.3. The B©*ttiker-Landauer approach – 6.4. The fractional quantum Hall effect.
7. Spin – 7.1. The spin Hall effect – 7.2. Spin injection – 7.3. Spin currents in nanowires – 7.4. Spin relaxation – Appendix F. Spin angular momentum – Appendix G. The Bloch sphere.
8. Tunnel devices – 8.1. Coulomb blockade – 8.2. Single-electron structures – 8.3. Quantum dots and qubits – 8.4. Resonant tunneling diodes – Appendix H. Simple tunneling – Appendix I. The Darwin-Fock spectrum.
9. Open quantum dots – 9.1. Conductance fluctuations in open dots – 9.2. Pointer states – 9.3. Hybrid states – 9.4. Imaging the pointer state scar.
10. Hot carriers in mesoscopic devices – 10.1. Energy-loss rates – 10.2. The energy-relaxation time.
Graduate students and researchers in semiconductor physics and devices.
Also available in print.
Mode of access: World Wide Web.
System requirements: Adobe Acrobat Reader.
David K. Ferry is Regents' Professor in the School of Electrical, Computer, and Energy Engineering, at Arizona State University. He received his doctoral degree from the University of Texas, Austin, and was the recipient of the 1999 Cledo Brunetti Award from the Institute of Electrical and Electronics Engineers for his contributions to nanoelectronics. He is the author, or co-author, of numerous scientific articles and more than a dozen books.
IOP expanding physics.
View this book online, via Institute of Physics, both on- and off-campus},
   pages = {(Various Pagings)},
   title = {Transport in semiconductor mesoscopic devices}
}
@article{FinnemorDk1966,
   author = {Finnemor.Dk and Stromber.Tf and C A Swenson},
   issue = {1},
   journal = {Physical Review},
   note = {82198
Times Cited:312
Cited References Count:63},
   pages = {231-+},
   title = {Superconducting Properties of High-Purity Niobium},
   volume = {149},
   year = {1966}
}
@book{H1989,
   author = {Marian A H. and Helmut S.},
   keywords = {Molecular beam epitaxy.},
   note = {M.A. Herman, H. Sitter.},
   pages = {1-20},
   publisher = {Springer},
   title = {Molecular beam epitaxy : fundamentals and current status},
   year = {1989}
}
@misc{,
   author = {Chihiro Hamaguchi},
   isbn = {9783642033032
3642033032},
   keywords = {Semiconductors.
Electronic books.},
   note = {[electronic resource] / Chihiro Hamaguchi.
Includes bibliographical references (pages 549-562) and index.},
   pages = {1 online resource (xv, 570 pages)},
   title = {Basic semiconductor physics}
}
@book{,
   author = {Chihiro Hamaguchi},
   edition = {Second edition.},
   keywords = {Semiconductors.},
   note = {Chihiro Hamaguchi.
illustrations ; ; 24 cm
Includes bibliographical references (pages [549]-562) and index.},
   pages = {pp 287-293},
   publisher = {Springer},
   title = {Basic semiconductor physics}
}
@book{,
   author = {Chihiro Hamaguchi},
   keywords = {Semiconductors.},
   note = {2001031177
Chihiro Hamaguchi.
24 cm
Includes bibliographical references and index.},
   pages = {xii, 434 pages},
   title = {Basic semiconductor physics}
}
@book{,
   author = {P Harrison and Alex Valavanis},
   edition = {Fourth edition.},
   keywords = {Quantum wells.
Nanowires.
Quantum dots.
Electronic books.},
   note = {2015045402
(OCoLC)929985364
(Paul),
Paul Harrison, Alex Valavanis.
Includes bibliographical references and index.
Semiconductors and heterostructures – Solutions to Schr©œdinger's equation – Numerical solutions – Diffusion – Impurities – Excitons – Strained quantum wells – Simple models of quantum wires and dots – Quantum dots – Carrier scattering – Optical properties of quantum wells – Carrier transport – Optical waveguides – Multiband envelope function (k.p) method – Empirical pseudo-potential bandstructure – Pseudo-potential calculations of nanostructures.
View this book online, via DawsonERA, both on- and off-campus},
   pages = {1 online resource (xxvi, 598 pages)},
   title = {Quantum wells, wires and dots : theoretical and computational physics of semiconductor nanostructures}
}
@misc{,
   author = {Ivan Knez},
   institution = {Rice University, 2012.},
   note = {by Ivan Knez.
28 cm.
Physics and Astronomy
Physics and Astronomy.},
   title = {Transport properties of topological phases in broken gap inAs/GaSb based quantum wells}
}
@book{,
   author = {Donald A Neamen},
   keywords = {Semiconductors.},
   note = {91031944
Donald A. Neamen.
color illustrations ; 24 cm
Includes bibliographical references and index.},
   pages = {xx, 746 pages},
   title = {Semiconductor physics and devices : basic principles}
}
@article{Reed1986,
   author = {M A Reed and W P Kirk and P S Kobiela},
   issue = {9},
   journal = {IEEE Journal of Quantum Electronics},
   pages = {1753-1759},
   title = {Investigation of Parallel Conduction in {GaAs/Al$_X$Ga$_{1-X}$As} Modulation-Doped Structures in the Quantum Limit},
   volume = {22},
   year = {1986}
}
@book{,
   author = {Fausto Rossi},
   keywords = {Semiconductors.
Quantum dots.},
   note = {edited by Fausto Rossi.
illustrations ; 24 cm
Includes bibliographical references and index.},
   pages = {319 pages},
   title = {Semiconductor macroatoms : basic physics and quantum-device applications}
}
@article{Paulo2002,
   abstract = {We propose a general method for describing tapping-mode atomic-force microscopy. The combined participation of attractive and repulsive interactions determines the multivalued nature of the resonance curve. This, in turn, implies the coexistence of two different stable oscillations for some excitation frequencies. The coexistence of two stable oscillations depends on the driving force and tip-surface separation. Increasing the driving force inhibits the low-amplitude oscillation state. Because resolution depends on the oscillation state, we propose that the absence of the low amplitude solution is responsible for the inconsistencies observed in high-resolution imaging of biomolecules.},
   author = {A San Paulo and R Garcia},
   issue = {4},
   journal = {Physical Review B},
   keywords = {sample interaction regimes
intermittent contact
tip
phase
contrast
dynamics
kinetics
surface
system
scale},
   note = {583UA
Times Cited:141
Cited References Count:23},
   pages = {41406},
   title = {Unifying theory of tapping-mode atomic-force microscopy},
   volume = {66},
   year = {2002}
}
@article{vanHall1989,
   author = {P J van Hall},
   issue = {2},
   journal = {Superlattices and Microstructures},
   note = {Af009
Times Cited:20
Cited References Count:13},
   pages = {213-216},
   title = {Remote Impurity Scattering in GaAs-AlGaAs Heterojunctions},
   volume = {6},
   year = {1989}
}
@article{vanHall1988,
   author = {P J van Hall and T Klaver and J H Wolter},
   issue = {2},
   journal = {Semiconductor Science and Technology},
   note = {M1428
Times Cited:18
Cited References Count:0},
   pages = {120-123},
   title = {Remote Impurity Scattering in Heterojunctions},
   volume = {3},
   year = {1988}
}
@article{VanvechtJa1969,
   author = {Vanvecht.Ja},
   issue = {3},
   journal = {Bulletin of the American Physical Society},
   note = {C6746
Times Cited:0
Cited References Count:0},
   pages = {317-&},
   title = {Quantum Dielectric Theory of Electronegativity in Covalent Systems .I. Electronic Dielectric Constant},
   volume = {14},
   year = {1969}
}
@article{VanvechtJa1969,
   author = {Vanvecht.Ja},
   issue = {3},
   journal = {Bulletin of the American Physical Society},
   note = {C6746
Times Cited:0
Cited References Count:0},
   pages = {317-&},
   title = {Quantum Dielectric Theory of Electronegativity in Covalent Systems .I. Electronic Dielectric Constant},
   volume = {14},
   year = {1969}
}
@article{vonKlitzing2005,
   abstract = {The most important applications of the quantum Hall effect (QHE) are in the field of metrology. The observed quantization of the resistance is primarily used for the reproduction of the SI unit ohm, but is also important for high precision measurements of both the fine structure constant and the Planck constant. Some current QHE research areas include the analysis of new electron electron correlation phenomena and the development of a more complete microscopic picture of this quantum effect. Recently, scanning force microscopy (SFM) of the potential distribution in QHE devices has been used to enhance the microscopic understanding of current flow in quantum Hall systems. This confirms the importance of the theoretically predicted stripes of compressible and incompressible electronic states close to the boundary of the QHE devices.},
   author = {K von Klitzing},
   issue = {1834},
   journal = {Philosophical Transactions of the Royal Society a-Mathematical Physical and Engineering Sciences},
   keywords = {quantum hall effect
fine structure constant
planck constant
von klitzing constant
electrical resistance
resistance
heterostructures
magnetotransport
electrostatics
standards
constant
physics
states
bipm},
   note = {967PT
Times Cited:13
Cited References Count:38},
   pages = {2203-2219},
   title = {Developments in the quantum Hall effect},
   volume = {363},
   year = {2005}
}
@article{deVries2017,
   author = {Arjan J A Beukman.
Folkert K de Vries. and Jasper van Veen. and Rafal Skolasinski. and Michael Wimmer.},
   issue = {24},
   journal = {Physical Review B},
   title = {Spin-orbit interaction in a dual gated InAs/GaSb quantum well},
   volume = {96},
   year = {2017}
}
@article{X2016,
   author = {Xiao X. and Y Liu and Z Liu and G Ai and S Yang and G Zhou},
   issue = {2},
   journal = {Applied Physics Letters},
   title = {All-electric spin modulator based on a two-dimensional topological insulator},
   volume = {108},
   year = {2016}
}
@article{Fulop2014,
   abstract = {A previously unreported phase transition between Bi2Te 3 and Bi4Te3 in bismuth telluride grown by molecular beam epitaxy is recorded via XRD, AFM, and SIMS observations. This transition is found to be related to the Te/Bi beam equivalent pressure (BEP) ratio. BEP ratios below 17 favor the formation of Bi4Te3 while Bi2Te3 is formed at higher ratios. Transport measurements reveal that Bi2Te3 has higher electron mobility than Bi4Te3. © 2014 The Japan Society of Applied Physics.},
   author = {Attila Fülöp and Yuxin Song and Sophie Charpentier and Peixiong Shi and Maria Ekström and Luca Galletti and Riccardo Arpaia and Thilo Bauch and Floriana Lombardi and Shumin Wang},
   doi = {10.7567/APEX.7.045503},
   issn = {18820786},
   issue = {4},
   journal = {Applied Physics Express},
   month = {10},
   pages = {45503},
   publisher = {Japan Society of Applied Physics},
   title = {Phase transition of bismuth telluride thin films grown by MBE},
   volume = {7},
   year = {2014}
}
@article{Koma1992,
   abstract = {One of the major obstacles to realizing various kinds of epitaxial heterostructure is the lattice matching between constituent materials. The lattice-matching condition, however, has been found to be drastically relaxed when the epitaxial growth proceeds with van der Waals interactions. Many kinds of layered material are suitable for that purpose. They are easily cleaved along the layers without producing dangling bonds on their cleaved surfaces. The epitaxial growth of a layered material onto those surfaces proceeds with a van der Waals force, resulting in good heteroepitaxial growth even with a large lattice mismatch between the grown and the substrate materials. It has also been found that van der Waals epitaxy can be applied to the epitaxial growth of a layered material on an ordinary three-dimensional material substrate, if regular termination of the surface dangling bonds is accomplished. Sulphur or selenium-atom-terminated GaAs(111), H-atom-terminated Si(111) and F-atom-terminated CaF2(111) surfaces can be used for that purpose. van der Waals epitaxy has also been successfully applied to grow such organic molecular crystal films as metal phthalocyanines, higher aromatics and C60. © 1992.},
   author = {Atsushi Koma},
   doi = {10.1016/0040-6090(92)90872-9},
   issn = {00406090},
   issue = {1},
   journal = {Thin Solid Films},
   month = {10},
   pages = {72-76},
   publisher = {Elsevier},
   title = {Van der Waals epitaxy-a new epitaxial growth method for a highly lattice-mismatched system},
   volume = {216},
   year = {1992}
}
@article{Yang1990,
   abstract = {Alkali halide single crystals are shown to grow well from molecular beams over a wide temperature range (0.10.5)Tm, where Tm is the melting temperature. Growth characteristics for homoepitaxy and heteroepitaxy, for alloys and superlattices, are discussed and found systematically different from those of metals and semiconductors. The reasons are related here to the type of lattice cohesion. © 1990 The American Physical Society.},
   author = {M H Yang and C P Flynn},
   doi = {10.1103/PhysRevB.41.8500},
   issn = {01631829},
   issue = {12},
   journal = {Physical Review B},
   month = {10},
   pages = {8500-8508},
   publisher = {American Physical Society},
   title = {Growth of alkali halides by molecular-beam epitaxy},
   volume = {41},
   year = {1990}
}
@inproceedings{Hor2011,
   abstract = {We show that by Ca doping the Bi2Se3 topological insulator, the Fermi level can be fine tuned to fall inside the band gap and therefore suppresses the bulk conductivity. Non-metallic Bi2Se 3 crystals are obtained. On the other hand, the Bi2Se 3 topological insulator can also be induced to become a bulk superconductor, with Tc∼3.8 K, by copper intercalation in the van der Waals gaps between the Bi2Se3 layers. Likewise, an as-grown crystal of metallic Bi2Te3 can be turned into a non-metallic crystal by slight variation in the Te content. The Bi 2Te3 topological insulator shows small amounts of superconductivity with Tc∼5.5 K when reacted with Pd to form materials of the type PdzBi2Te3. © 2010 Elsevier Ltd.All rights reserved.},
   author = {Y S Hor and J G Checkelsky and D Qu and N P Ong and R J Cava},
   doi = {10.1016/j.jpcs.2010.10.027},
   issn = {00223697},
   issue = {5},
   booktitle = {Journal of Physics and Chemistry of Solids},
   keywords = {A. Semiconductors,A. Superconductors,B. Crystal growth,D. Surface properties,D. Transport properties},
   month = {10},
   pages = {572-576},
   title = {Superconductivity and non-metallicity induced by doping the topological insulators Bi2Se3 and Bi2Te3},
   volume = {72},
   year = {2011}
}
@article{Rienks2019,
   abstract = {Magnetically doped topological insulators enable the quantum anomalous Hall effect (QAHE), which provides quantized edge states for lossless charge-transport applications1–8. The edge states are hosted by a magnetic energy gap at the Dirac point2, but hitherto all attempts to observe this gap directly have been unsuccessful. Observing the gap is considered to be essential to overcoming the limitations of the QAHE, which so far occurs only at temperatures that are one to two orders of magnitude below the ferromagnetic Curie temperature, TC (ref. 8). Here we use low-temperature photoelectron spectroscopy to unambiguously reveal the magnetic gap of Mn-doped Bi2Te3, which displays ferromagnetic out-of-plane spin texture and opens up only below TC. Surprisingly, our analysis reveals large gap sizes at 1 kelvin of up to 90 millielectronvolts, which is five times larger than theoretically predicted9. Using multiscale analysis we show that this enhancement is due to a remarkable structure modification induced by Mn doping: instead of a disordered impurity system, a self-organized alternating sequence of MnBi2Te4 septuple and Bi2Te3 quintuple layers is formed. This enhances the wavefunction overlap and size of the magnetic gap10. Mn-doped Bi2Se3 (ref. 11) and Mn-doped Sb2Te3 form similar heterostructures, but for Bi2Se3 only a nonmagnetic gap is formed and the magnetization is in the surface plane. This is explained by the smaller spin–orbit interaction by comparison with Mn-doped Bi2Te3. Our findings provide insights that will be crucial in pushing lossless transport in topological insulators towards room-temperature applications.},
   author = {E D L Rienks and S Wimmer and J Sánchez-Barriga and O Caha and P S Mandal and J Růžička and A Ney and H Steiner and V V Volobuev and H Groiss and M Albu and G Kothleitner and J Michalička and S A Khan and J Minár and H Ebert and G Bauer and F Freyse and A Varykhalov and O Rader and G Springholz},
   doi = {10.1038/s41586-019-1826-7},
   issn = {14764687},
   issue = {7787},
   journal = {Nature},
   month = {10},
   pages = {423-428},
   publisher = {Nature Research},
   title = {Large magnetic gap at the Dirac point in Bi2Te3/MnBi2Te4 heterostructures},
   volume = {576},
   year = {2019}
}
@article{Li2016,
   abstract = {Achieving a large thermoelectric figure of merit (ZT) value at elevated temperatures for Bi2Te3-based materials is significant for low-grade waste-heat (∼400-500 K) recovery applications. Here, we show that in Bi0.4Sb1.6Te3 based composites incorporated with 0.2 vol% CuO nanoinclusions, the introduced asymmetric interface potentials can effectively inhibit the transport of minorities through stronger scattering than majorities, as well as the energy filtering effect, thus resulting in an obvious increase (∼8% rise) of power factor at high temperatures. In addition to enhanced phonon scattering at interfaces and nanoinclusions, the reduced thermal conductivity (∼65% decline) at elevated temperatures can be attributed to inhibition of bipolar contributions through strong scattering of minorities at the interface potentials. Consequently, in BiSbTe-based thermoelectric systems with 0.2 vol% CuO, a largest ZT = 1.37 is achieved at 496 K, which is ∼40% larger than that of the BiSbTe matrix at the same temperature.},
   author = {Yuanyue Li and Guoxia Liu and Xiaoying Qin and Fukai Shan},
   doi = {10.1039/C6RA24107G},
   issn = {20462069},
   issue = {113},
   journal = {RSC Advances},
   month = {10},
   pages = {112050-112056},
   publisher = {Royal Society of Chemistry},
   title = {Inhibition of minority transport for elevating the thermoelectric figure of merit of CuO/BiSbTe nanocomposites at high temperatures},
   volume = {6},
   year = {2016}
}
@article{Wan1992,
   abstract = {The initial epitaxial growth of Bi on a Si(111)-7 × 7 surface has been studied as a function of overlayer coverage and deposition conditions using low-energy electron diffraction (LEED) and Auger electron spectroscopy (AES). Experiments show for the first time that two equilibrium phases are formed in the growth process, each displaying a (√3 × √3)R30° LEED symmetry: an α-phase occurring at 1 3 ML Bi coverage and substrate temperature of 360° C, and a β-phase at 1 ML and 300°C. Quantitative structural information for each phase was determined by multiple scattering analysis of I-V curves. The analysis is facilitated by comparing LEED intensity data measured for each phase with calculated values using appropriate structural models. The T4 geometry for the α-phase and a trimer geometry for the β-phase are revealed to be the "best" models; detailed atomic coordinates have been determined for each phase. © 1992.},
   author = {K J Wan and T Guo and W K Ford and J C Hermanson},
   doi = {10.1016/0039-6028(92)90219-V},
   issn = {00396028},
   issue = {1-3},
   journal = {Surface Science},
   month = {10},
   pages = {69-87},
   title = {Low-energy electron diffraction studies of Si(111)-(√3 × √3)R30°-Bi system: Observation and structural determination of two phases},
   volume = {261},
   year = {1992}
}
@misc{Walsh2017,
   abstract = {van der Waals epitaxy (VDWE) is an ideal method for growing 2D materials and topological insulators (TIs) onto a variety of substrates for heterostructure and integrated circuit technologies. The characteristics of VDWE include rotational alignment with the substrate, strain-free growth, and no misfit dislocations despite significant lattice mismatch. Such properties are critical to enable devices which use the unique characteristics of transition metal dichalcogenides (TMDs) and TIs. These include defect tolerance, spin-polarized transport, reduced leakage currents, and tunable band gaps. In this review, the growth modes and advantages of VDWE are introduced along with a brief history of the field. Then the most important issues regarding the VDWE of TMDs and TIs in particular are discussed, including grain size control, defect density, doping, rotational alignment, and electronic transport. Finally, we provide an overview of the progress made in recent years along with an outlook to address the remaining issues facing VDWE and these materials.},
   author = {Lee A Walsh and Christopher L Hinkle},
   doi = {10.1016/j.apmt.2017.09.010},
   issn = {23529407},
   journal = {Applied Materials Today},
   keywords = {2D materials,Molecular beam epitaxy,Topological insulators,Transition metal dichalcogenides,van der Waals materials},
   month = {10},
   pages = {504-515},
   publisher = {Elsevier Ltd},
   title = {van der Waals epitaxy: 2D materials and topological insulators},
   volume = {9},
   year = {2017}
}
@misc{Manivannan1991,
   author = {Ayyakkannu Manivannan and Hajime Hoshi and Larry A Nagahara and al - and Akihiko Fujii and Hiroyoshi Mizukami and Shinji Hiwatashi},
   journal = {Japanese Journal of Applied Physics To},
   pages = {1892},
   title = {Van der Waals Epitaxial Growth of C 60 Film on a Cleaved Face of MoS 2},
   volume = {30},
   year = {1991}
}
@article{Hashimoto2008,
   abstract = {We have investigated on the van der Waals epitaxy of a solid C60 layer on a graphene sheet and have first successfully achieved it. It is expected that the hetero-structures of the solid C60 layer and the graphene sheet opens new opportunities in the carbon nano-electronics. © 2008 Elsevier B.V. All rights reserved.},
   author = {Akihiro Hashimoto and Kohsuke Iwao and Satoru Tanaka and Akio Yamamoto},
   doi = {10.1016/j.diamond.2008.03.011},
   issn = {09259635},
   issue = {7-10},
   journal = {Diamond and Related Materials},
   keywords = {Graphene,Solid C60 layer,van der Waals epitaxy},
   month = {10},
   pages = {1622-1624},
   title = {van der Waals epitaxy of solid C60 on graphene sheet},
   volume = {17},
   year = {2008}
}
@article{Latzke2019,
   abstract = {While long-theorized, the direct observation of multiple highly-dispersive C60 valence bands has eluded researchers for more than two decades due to a variety of intrinsic and extrinsic factors. Here we report the first realization of multiple highly-dispersive (330-520 meV) valence bands in pure thin film C60 on a novel substrate-the three dimensional topological insulator Bi2Se3-through the use of angle-resolved photoemission spectroscopy (ARPES) and first-principles calculations. The effects of this novel substrate reducing C60 rotational disorder are discussed. Our results provide important considerations for past and future band structure studies as well as the increasingly popular C60 electronic device applications, especially those making use of heterostructures.},
   author = {Drew W Latzke and Claudia Ojeda-Aristizabal and Sinéad M Griffin and Jonathan D Denlinger and Jeffrey B Neaton and Alex Zettl and Alessandra Lanzara},
   doi = {10.1103/PhysRevB.99.045425},
   journal = {Phys. Rev. B},
   title = {Observation of highly dispersive bands in pure thin film C_{60}},
   year = {2019}
}
@article{Taskin2012,
   abstract = {The massless Dirac fermions residing on the surface of three-dimensional topological insulators are protected from backscattering and cannot be localized by disorder, but such protection can be lifted in ultrathin films when the three-dimensionality is lost. By measuring the Shubnikov-de Haas oscillations in a series of high-quality Bi 2 Se 3 thin films, we revealed a systematic evolution of the surface conductance as a function of thickness and found a striking manifestation of the topological protection: The metallic surface transport abruptly diminishes below the critical thickness of 6 nm, at which an energy gap opens in the surface state and the Dirac fermions become massive. At the same time, the weak antilocalization behavior is found to weaken in the gapped phase due to the loss of Berry phase. In topological insulators (TIs) the energy states are fundamentally modified from ordinary insulators by strong spin-orbit interactions, giving rise to a topologically distinct state of matter with a gapped insulating bulk and a gapless metallic surface [1]. Various interesting phenomena , including surface transport of spin-filtered Dirac fermions that are immune to localization, have been predicted and raised expectations for novel applications [2-4]. However, the progress in real applications of TIs crucially relies on the ability to manipulate the surface current in transport experiments. At present, such basic characterization as the surface conductance measurement has been possible only in a few cases in single crystals [5-12] because of the dominance of bulk transport caused by unintentional doping due to defects. Molecular beam epi-taxy (MBE) is a promising technique for the synthesis of TIs [13-18] owing, in part, to the relatively low deposition temperature at which defect concentrations can be reduced from those in bulk crystals grown in thermal equilibrium. So far, using MBE-grown films, angle-resolved photoemis-sion spectroscopy (ARPES) [19] and scanning tunneling spectroscopy (STS) [20] have provided useful information about the topological surface state (SS), and in transport experiments, such phenomena as weak antilocalization (WAL) and gate-controlled ambipolar transport have been reported [21,22]. Also, since the MBE technique gives a precise control over film thickness, transport measurements for widely varying surface-to-bulk conductivity ratio have been performed [23-25], although a reliable separation of surface Dirac electrons from bulk carriers has been hindered by a relatively low mobility of carriers in available thin films. Recently, we have succeeded in growing high-quality epitaxial films of Bi 2 Se 3 that have a sufficiently high surface electron mobility to present pronounced Shubnikov-de Haas (SdH) oscillations. This made it possible to directly probe the surface conductance and the topological protection of the SS.},
   author = {A A Taskin and Satoshi Sasaki and Kouji Segawa and Yoichi Ando},
   doi = {10.1103/PhysRevLett.109.066803},
   journal = {Physical Review Letters},
   title = {Manifestation of Topological Protection in Transport Properties of Epitaxial Bi 2 Se 3 Thin Films},
   year = {2012}
}
@article{Bansal2011,
   abstract = {Atomically sharp epitaxial growth of Bi2Se3 films is achieved on Si(111) substrate with molecular beam epitaxy. Two-step growth process is found to be a key to achieve interfacial-layer-free epitaxial Bi 2Se3 films on Si substrates. With a single-step high temperature growth, second phase clusters are formed at an early stage. On the other hand, with low temperature growth, the film tends to be disordered even in the absence of a second phase. With a low temperature initial growth followed by a high temperature growth, second-phase-free atomically sharp interface is obtained between Bi2Se3 and Si substrate, as verified by reflection high energy electron diffraction (RHEED), transmission electron microscopy (TEM) and X-ray diffraction. The lattice constant of Bi 2Se3 is observed to relax to its bulk value during the first quintuple layer according to RHEED analysis, implying the absence of strain from the substrate. TEM shows a fully epitaxial structure of Bi 2Se3 film down to the first quintuple layer without any second phase or an amorphous layer. © 2011 Elsevier B.V.},
   author = {Namrata Bansal and Yong Seung Kim and Eliav Edrey and Matthew Brahlek and Yoichi Horibe and Keiko Iida and Makoto Tanimura and Guo Hong Li and Tian Feng and Hang Dong Lee and Torgny Gustafsson and Eva Andrei and Seongshik Oh},
   doi = {10.1016/j.tsf.2011.07.033},
   issn = {00406090},
   issue = {1},
   journal = {Thin Solid Films},
   keywords = {Bismuth selenide,Interface structure,Molecular beam epitaxy,Reflection high energy electron diffraction,Silicon,Topological insulators,Transmission electron microscopy},
   month = {10},
   pages = {224-229},
   title = {Epitaxial growth of topological insulator {Bi$_2$Se$_3$} film on {Si(111)} with atomically sharp interface},
   volume = {520},
   year = {2011}
}
@article{Young2011,
   abstract = {The topological insulating phase results from inversion of the band gap due to spin-orbit coupling at an odd number of time-reversal symmetric points. In Bi 2 Se 3 , this inversion occurs at the point. For bulk Bi 2 Se 3 , we have analyzed the effect of arbitrary strain on the point band gap using density functional theory. By computing the band structure both with and without spin-orbit interactions, we consider the effects of strain on the gap via Coulombic interaction and spin-orbit interaction separately. While compressive strain acts to decrease the Coulombic gap, it also increases the strength of the spin-orbit interaction, increasing the inverted gap. Comparison with Bi 2 Te 3 supports the conclusion that effects on both Coulombic and spin-orbit interactions are critical to understanding the behavior of topological insulators under strain, and we propose that the topological insulating phase can be effectively manipulated by inducing strain through chemical substitution.},
   author = {Steve M Young and Sugata Chowdhury and Eric J Walter and Eugene J Mele and Charles L Kane and Andrew M Rappe},
   doi = {10.1103/PhysRevB.84.085106},
   journal = {PHYSICAL REVIEW B},
   keywords = {6220−x,6470−p,7130+h,number(s): 0365Vf},
   pages = {85106},
   title = {Theoretical investigation of the evolution of the topological phase of {Bi$_2$Se$_3$} under mechanical strain},
   volume = {84},
   year = {2011}
}
@article{Moorsom2014,
   author = {Timothy Moorsom and May Wheeler and Taukeer Khan and Fatma Al Ma'mari and Gavin Burnell and Bryan J Hickey and Vlado Lazarov and Daniel Gilks and Oscar Cespedes},
   doi = {10.1063/1.4885336},
   journal = {Appl. Phys. Lett},
   pages = {22408},
   title = {Effects of spin doping and spin injection in the luminescence and vibrational spectrum of C60},
   volume = {105},
   url = {http://dx.doi.org/10.1063/1.4885336]},
   year = {2014}
}
@article{Barcote2019,
   abstract = {This paper presents a study on the lattice dynamics of doped topological insulator (Cu,Ni)xBi2Se3 single crystals probed using Raman scattering spectroscopy. The single crystals were grown by melting and characterized through X-ray diffraction and scanning electron microscopy with energy dispersive X-ray spectroscopy. The diffraction patterns were indexed within the space group R-3m and the samples belonged to the rhombohedral layered structure group typical of Bi2Se3. A Raman scattering study was developed, in which three modes were observed at low frequencies: A1g1, Eg2 and A1g2. The low frequency Eg1 mode, even if theoretically predicted, was not observed. No difference was observed in Raman lines between the pure and (Cu,Ni)-doped samples, indicating that the Cu and Ni are probably intercalated (and not substituted) between the Se layers.},
   author = {Marcos Vinicius Woiski Barcote and Everton de Andrade and Alcione Roberto Jurelo and João Frederico Haas Leandro Monteiro and Ezequiel Costa Siqueira},
   doi = {10.1016/j.matchemphys.2018.10.053},
   issn = {02540584},
   journal = {Materials Chemistry and Physics},
   keywords = {Bismuth selenide,Cu,Ni,Raman spectroscopy,Topological insulators},
   month = {10},
   pages = {109-113},
   publisher = {Elsevier Ltd},
   title = {Raman spectroscopy of the doped topological insulator (Cu,Ni)xBi2Se3},
   volume = {223},
   year = {2019}
}
@misc{Akers1994,
   abstract = {Two distinct Raman spectra have been reported for solid Ceo· They differ in the exact position and relative intensities of the spectral lines. Specifically, the frequency of the pentagonal pinch mode occurs at 1469 and 1459 cm-1 in the two spectra. Several explanations have been offered for the existence of a second spectrum, including the influence of interstitial oxygen, a change in phase, the coexistence of singlet Ceo with laser-pumped triplet C6o, and photopolymerization. We show that there are two Raman spectra for solid films of Ceo with varying relative intensities according to the sample temperature even in the absence of oxygen. The reversibility of the two forms of C6o with temperature argues against photopolymerization. Finally pump-probe experiments designed to detect either triplet absorption or singlet depletion indicate that neither of the two Raman spectra are due to triplet Ceo-We conclude that our previous explanation in terms of two phases of C6o is still the most consistent with the observations.},
   author = {Kelly L Akers and Constantine Douketis and Tom L Haslett and Martin Moskovits},
   journal = {J. Phys. Chem},
   pages = {10824-10831},
   title = {Raman Spectroscopy of Ceo Solid Films: A Tale of Two Spectra},
   volume = {98},
   url = {https://pubs.acs.org/sharingguidelines},
   year = {1994}
}
@article{Weyrich2017,
   abstract = {Quantum oscillations in three-dimensional topological insulators S I Vedeneev-Recent citations Effect of quenching on the electrical and optical properties of MoTe 2 V V Marchenkov et al-Trivial band topology of ultra-thin rhombohedral Sb 2 Se 3 grown on Bi 2 Se 3 A V Matetskiy et al-The heterostructure and electrical properties of Sb2Se3/Bi2Se3 grown by molecular beam epitaxy You-Jyun Chen et al-This content was downloaded from IP address 88.98.242.112 on 14/04/2020 at 15:11},
   author = {C Weyrich and M Drögeler and J Kampmeier and al - and Yang Wen-Min and Lin Chao-Jing and Liao Jian},
   doi = {10.7567/JJAP.56.070311},
   journal = {Japanese Journal of Applied Physics RAPID COMMUNICATIONS},
   pages = {70311},
   title = {Growth and characterization of MBE-grown (Bi 1− x Sb x ) 2 Se 3 topological insulator Related content Growth, characterization, and transport properties of ternary (Bi1xSbx)2Te3 topological insulator layers Electrostatic field effects on three-dimensional topological insulators},
   volume = {56},
   url = {https://doi.org/10.7567/JJAP.56.070311},
   year = {2017}
}
@article{Bansal2014,
   abstract = {Mechanical exfoliation of bulk crystals has been widely used to obtain thin topological insulator (TI) flakes for device fabrication. However, such a process produces only microsized flakes that are highly irregular in shape and thickness. In this work, we developed a process to transfer the entire area of TI Bi 2 Se 3 thin films grown epitaxially on Al 2 O 3 and SiO 2 to arbitrary substrates, maintaining their pristine morphology and crystallinity. Transport measurements show that these transferred films have lower carrier concentrations and comparable or higher mobilities than before the transfer. Furthermore, using this process we demonstrated a clear metal−insulator transition in an ultrathin Bi 2 Se 3 film by gate-tuning its Fermi level into the hybridization gap formed at the Dirac point. The ability to transfer large area TI films to any substrate will facilitate fabrication of TI heterostructure devices, which will help explore exotic phenomena such as Majorana fermions and topological magnetoelectricity. KEYWORDS: Topological insulator, bismuth selenide, metal−insulator transition, thin film transfer, electric field effect T opological insulators (TI) are nonmagnetic insulators that have a gapped bulk band but protected metallic surface states as a consequence of spin−orbit interactions and time-reversal symmetry. 1−4 Band structure topology of these materials coupled with the spin-momentum locking mechanism prevents these metallic surface states from backscattering and localization. 5−9 Bi 2 Se 3 is one of the most extensively studied TI materials as it has the simplest surface state structure and a relatively large band gap of 0.3 eV. 10 Bi 2 Se 3 has a rhombohedral structure with a sequence of Se−Bi−Se−Bi-Se forming a quintuple layer (QL, 1 QL ≈ 1 nm) along the c-axis direction. This layered structure is held together strongly within the QL but only weakly between layers by van der Waals forces. 11,12 Significant progress has been made in understanding the properties of TIs through angle resolved photoemission spectroscopy (ARPES), 8,13−15 scanning tunneling microscopy 7 and transport measurements. 16−25 Recently, there is a growing interest in combining TIs with superconductors, (anti)-ferromagnets, and so forth in search of quantum anomalous Hall effect, 26,27 Majorana fermions, 28,29 or other magneto-electric effects. 30,31 The weak interlayer bonding enables mechanical exfoliation of thin Bi 2 Se 3 flakes from bulk crystals and such flakes have been extensively used to fabricate TI devices. 16−20,32,33 However, the process of mechanically cleaving bulk crystals results in flakes of limited lateral sizes and ill-defined thicknesses and the yield of obtaining ultrathin flakes (≤10 nm) is very low. 20,32,34,35 On the other hand, techniques to transfer large-area 2D layered materials are well established in the field of graphene. A polymeric supporting layer has been successfully demonstrated as a transferring template for various 2D materials such as graphene, 36,37 hexagonal boron nitride, 38 molybdenum disulfide, 39 and so forth. However, such a process has not been developed for TI structures yet. Herein, we demonstrate that large-area Bi 2 Se 3 films grown by molecular beam epitaxy (MBE) on Al 2 O 3 (0001) and amorphous SiO 2 (a-SiO 2) substrates can be transferred onto various substrates, including a common transparency sheet. This transfer process opens a new door for TI research in that MBE allows not only precise control in film thickness but also formation of novel heterostructures that cannot be achieved with other synthesis methods.},
   author = {Namrata Bansal and Myung Rae Cho and Matthew Brahlek and Nikesh Koirala and Yoichi Horibe and Jing Chen and Weida Wu and Yun Daniel Park and Seongshik Oh},
   doi = {10.1021/nl404363b},
   journal = {Nano Lett},
   title = {Transferring MBE-Grown Topological Insulator Films to Arbitrary Substrates and Metal−Insulator Transition via Dirac Gap},
   volume = {14},
   url = {https://pubs.acs.org/sharingguidelines},
   year = {2014}
}
@article{Yan2013,
   abstract = {Although topological surface states are known to be robust against nonmagnetic surface perturbations, their band dispersions and spatial distributions are still sensitive to surface defects. Taking Bi2Se3 as an example, we demonstrate that Se vacancies modify the surface band structures considerably. When large numbers of Se vacancies exist on the surface, topological surface states may sink down from the first to the second quintuple layer and get separated from the vacancies. We simulated scanning tunnelling microscopy images to distinguish surfaces with Se and Bi terminations. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.},
   author = {Binghai Yan and Delin Zhang and Claudia Felser},
   doi = {10.1002/pssr.201206415},
   issn = {18626254},
   issue = {1-2},
   journal = {physica status solidi (RRL) - Rapid Research Letters},
   keywords = {BiSe,First-principles calculations,STM,Se,Vacancies},
   month = {10},
   pages = {148-150},
   publisher = {John Wiley \& Sons, Ltd},
   title = {Topological surface states of Bi <sub>2</sub> Se <sub>3</sub> coexisting with Se vacancies},
   volume = {7},
   url = {http://doi.wiley.com/10.1002/pssr.201206415},
   year = {2013}
}
@article{Lin2013,
   abstract = {We investigate the topological surface state properties at various surface cleaves in the topological insulator Bi2Se3, via first principles calculations and scanning tunneling microscopy/spectroscopy (STM/STS). While the typical surface termination occurs between two quintuple layers, we report the existence of a surface termination within a single quintuple layer where dangling bonds form with giant spin splitting owing to strong spin-orbit coupling. Unlike Rashba split states in a 2D electron gas, these states are constrained by the band topology of the host insulator with topological properties similar to the typical topological surface state, and thereby offer an alternative candidate for spintronics usage. We name these new states "topological dangling-bond states". The degree of the spin polarization of these states is greatly enhanced. Since dangling bonds are more chemically reactive, the observed topological dangling-bond states provide a new avenue for manipulating band dispersions and spin-textures by adsorbed atoms or molecules. © 2013 American Chemical Society.},
   author = {Hsin Lin and Tanmoy Das and Yoshinori Okada and Mike C Boyer and W Doug Wise and Michelle Tomasik and Bo Zhen and Eric W Hudson and Wenwen Zhou and Vidya Madhavan and Chung Yuan Ren and Hiroshi Ikuta and Arun Bansil},
   doi = {10.1021/nl304099x},
   issn = {15306984},
   issue = {5},
   journal = {Nano Letters},
   keywords = {Bi2Se3,Topological insulators,dangling bonds,electronic structures,scanning tunneling spectroscopy},
   month = {10},
   pages = {1915-1919},
   publisher = {American Chemical Society},
   title = {Topological dangling bonds with large spin splitting and enhanced spin polarization on the surfaces of Bi2Se3},
   volume = {13},
   year = {2013}
}
@article{Song2010,
   abstract = {Atomically flat thin films of topological insulator Bi2 Se 3 have been grown on double-layer graphene formed on 6H-SiC(0001) substrate by molecular beam epitaxy. By a combined study of reflection high energy electron diffraction and scanning tunneling microscopy, we identified the Se-rich condition and temperature criterion for layer-by-layer growth of epitaxial Bi2 Se3 films. The as-grown films without doping exhibit a low defect density of 1.0±0.2× 1011 /cm2, and become a bulk insulator at a thickness of ten quintuple layers, as revealed by in situ angle resolved photoemission spectroscopy measurement. © 2010 American Institute of Physics.},
   author = {Can Li Song and Yi Lin Wang and Ye Ping Jiang and Yi Zhang and Cui Zu Chang and Lili Wang and Ke He and Xi Chen and Jin Feng Jia and Yayu Wang and Zhong Fang and Xi Dai and Xin Cheng Xie and Xiao Liang Qi and Shou Cheng Zhang and Qi Kun Xue and Xucun Ma},
   doi = {10.1063/1.3494595},
   issn = {00036951},
   issue = {14},
   journal = {Applied Physics Letters},
   keywords = {bismuth compounds,insulating thin films,molecular beam epitaxial growth,photoelectron spectra,reflection high energy electron diffraction,scanning tunnelling microscopy},
   month = {10},
   pages = {143118},
   publisher = {American Institute of Physics},
   title = {Topological insulator {Bi$_2$Se$_3$} thin films grown on double-layer graphene by molecular beam epitaxy},
   volume = {97},
   url = {http://aip.scitation.org/doi/10.1063/1.3494595},
   year = {2010}
}
@article{Kitamura1991,
   abstract = {An understanding of the kinetics of structural phase transitions in crystalline, semiconducting thin films is important for the control of film growth in techniques such as molecular-beam epitaxy, as well as in applications of such films at high temperatures. Electron diffraction techniques (LEED and RHEED) have been applied to the study of high-temperature surface reconstruction, but although these can detect changes in surface periodicity, they do not permit atomic-scale resolution of the nucleation and growth processes. The scanning tunnelling microscope (STM) provides an alternative tool to investigate changes of this sort, but high-temperature observations have been hampered by problems of thermal drift. Here we report our success in overcoming these problems and thus in obtaining atomic-resolution STM images of the 1 × 1 → 7 × 7 surface reconstruction of a silicon thin film at about 860°C. Step formation and migration are clearly visible in these images. © 1991 Nature Publishing Group.},
   author = {Shin Ichi Kitamura and Tomoshige Sato and Masashi Iwatsuki},
   doi = {10.1038/351215a0},
   issn = {00280836},
   issue = {6323},
   journal = {Nature},
   keywords = {Humanities and Social Sciences,Science,multidisciplinary},
   pages = {215-217},
   publisher = {Nature Publishing Group},
   title = {Observation of surface reconstruction on silicon above 800°C using the STM},
   volume = {351},
   year = {1991}
}
@article{Caywood1970,
   abstract = {Low-field galvanomagnetic coefficients have been measured on single crystals of Bi2Te3 and Bi2Se3 at 76 °K in fields to 9 kG. Using a six-valley ellipsoid model in the isotropic relaxation-time approximation, the mass parameters of the ellipsoids are calculated for both compounds. The discrepancy between previously reported galvanomagnetic data and de Haas-van Alphen data for Bi2Te3 can be minimized by recalculating the mass parameters from the galvanomagnetic data and by not assuming complete degeneracy. The experimental data on Bi2Te3 are in agreement with those reported earlier. There is also very good evidence of second-band effects at high electron concentrations (> 1019 cm-3), as has been previously suggested. The constant-energy surfaces undergo an apparent change in shape between low- and high-concentration samples. Data on Bi2Se3 indicate that the constant-energy surfaces are more spherical than in the case of Bi2Te3. © 1970 The American Physical Society.},
   author = {L P Caywood and G R Miller},
   doi = {10.1103/PhysRevB.2.3209},
   issn = {01631829},
   issue = {8},
   journal = {Physical Review B},
   month = {10},
   pages = {3209-3220},
   publisher = {American Physical Society},
   title = {Anistropy of the constant-energy surfaces in n-Type BiTe32 and Bi2Se3 from galvanomagnetic coefficients},
   volume = {2},
   year = {1970}
}
@article{Park2015,
   author = {Kyeong Hyun Park and Mohamed Mohamed and Zlatan Aksamija and Umberto Ravaioli},
   doi = {10.1063/1.4905294},
   journal = {J. Appl. Phys},
   pages = {15103},
   title = {Phonon scattering due to van der Waals forces in the lattice thermal conductivity of Bi 2 Te 3 thin films},
   volume = {117},
   url = {https://doi.org/10.1063/1.4905294},
   year = {2015}
}
@article{Jing2009,
   abstract = {Molecular vibration spectra are of great significance in the study of molecular structures and characters. A widely-used analytical method of structural mechanics, finite element method, is imported into the domain of micro-scaled molecular spectra. The vibrational modes of fullerenes C 60 and C 70 are calculated depending on uniform carbon-carbon bonding elements, each of which has three force constants that are determined by fitting the C 60 Raman spectra experimental data and one ratio factor which is the bond lengths ratio between the single and double bonds. The computational result shows reasonable agreement with both calculated and experimental results published before. Ó 2009 Published by Elsevier Masson SAS.},
   author = {Du Jing and Zeng Pan},
   doi = {10.1016/j.euromechsol.2009.02.006},
   journal = {European Journal of Mechanics / A Solids},
   keywords = {C70,Finite element method,Fullerene,Molecular spectra},
   pages = {948-954},
   title = {Molecular vibrational modes of C 60 and C 70 via finite element method},
   volume = {28},
   url = {http://me.tsinghua.edu.cn/zengp/dme310/eng/eng_index.htm},
   year = {2009}
}
@article{Goel2004,
   abstract = {Individual fullerene molecules were observed and sized using high resolution transmission electron microscopy. Fullerene C 60 molecules were tethered by chemical bonding to carbon black particles to facilitate HRTEM imaging and sizing of known fullerenes. HRTEM analysis of soot samples from a fullerene-forming flame revealed the presence of a range of fullerenes from C 36 to C 176 and larger fullerene-like structures. The observation of fullerenes smaller than C 60 is noteworthy in that such structures necessarily contain adjacent pentagons and hence are strained and expected to have interesting reactivity that may be useful in certain applications. HRTEM can be used to detect and size fullerenes in samples containing fullerenes but not in sufficient quantity, or not sufficiently removable, to be detectable by chemical analysis.},
   author = {Anish Goel and Jack B Howard and John B Vander Sande},
   doi = {10.1016/j.carbon.2004.03.022},
   keywords = {A Carbon black,C Electron microscopy,D Microstructure,Fullerene,Soot},
   title = {Size analysis of single fullerene molecules by electron microscopy},
   url = {www.elsevier.com/locate/carbon},
   year = {2004}
}
@article{Brahlek2011,
   abstract = {Topological insulators (TIs) are predicted to be composed of an insulating bulk state along with conducting channels on the boundary of the material. In Bi2Se3, however, the Fermi level naturally resides in the conduction band due to intrinsic doping by selenium vacancies, leading to metallic bulk states. In such non-ideal TIs, it is not well understood how the surface and bulk states behave under environmental disorder. In this letter, based on transport measurements of Bi2Se3 thin films, we show that the bulk states are sensitive to environmental disorder but the surface states remain robust. © 2011 American Institute of Physics.},
   author = {Matthew Brahlek and Yong Seung Kim and Namrata Bansal and Eliav Edrey and Seongshik Oh},
   doi = {10.1063/1.3607484},
   issn = {00036951},
   issue = {1},
   journal = {Applied Physics Letters},
   keywords = {Fermi level,bismuth compounds,conduction bands,doping,insulating thin films,surface states,topological insulators,vacancies (crystal)},
   month = {10},
   pages = {12109},
   publisher = {American Institute of Physics},
   title = {Surface versus bulk state in topological insulator {Bi$_2$Se$_3$} under environmental disorder},
   volume = {99},
   url = {http://aip.scitation.org/doi/10.1063/1.3607484},
   year = {2011}
}
@article{Walsh2018,
   abstract = {The topologically protected surface states of three-dimensional (3D) topological insulators have the potential to be transformative for high-performance logic and memory devices by exploiting their specific properties such as spin-polarized current transport and defect tolerance due to suppressed backscattering. However, topological insulator based devices have been underwhelming to date primarily due to the presence of parasitic issues. An important example is the challenge of suppressing bulk conduction in Bi2Se3 and achieving Fermi levels (EF) that reside in between the bulk valence and conduction bands so that the topologically protected surface states dominate the transport. The overwhelming majority of the Bi2Se3 studies in the literature report strongly n-type materials with EF in the bulk conduction band due to the presence of a high concentration of selenium vacancies. In contrast, here we report the growth of near-intrinsic Bi2Se3 with a minimal Se vacancy concentration providing a Fermi level near midgap with no extrinsic counter-doping required. We also demonstrate the crucial ability to tune EF from below midgap into the upper half of the gap near the conduction band edge by controlling the Se vacancy concentration using post-growth anneals. Additionally, we demonstrate the ability to maintain this Fermi level control following the careful, low-temperature removal of a protective Se cap, which allows samples to be transported in air for device fabrication. Thus, we provide detailed guidance for EF control that will finally enable researchers to fabricate high-performance devices that take advantage of transport through the topologically protected surface states of Bi2Se3.},
   author = {Lee A Walsh and Avery J Green and Rafik Addou and Westly Nolting and Christopher R Cormier and Adam T Barton and Tyler R Mowll and Ruoyu Yue and Ning Lu and Jiyoung Kim and Moon J Kim and Vincent P Labella and Carl A Ventrice and Stephen McDonnell and William G Vandenberghe and Robert M Wallace and Alain Diebold and Christopher L Hinkle},
   doi = {10.1021/acsnano.8b03414},
   issn = {1936086X},
   issue = {6},
   journal = {ACS Nano},
   keywords = {Fermi level,bismuth selenide,doping,molecular beam epitaxy,topological insulator},
   month = {10},
   pages = {6310-6318},
   publisher = {American Chemical Society},
   title = {Fermi Level Manipulation through Native Doping in the Topological Insulator Bi2Se3},
   volume = {12},
   year = {2018}
}
@article{Chen2009,
   abstract = {Three-dimensional topological insulators are a new state of quantum matter with a bulk gap and odd number of relativistic Dirac fermions on the surface. By investigating the surface state of Bi2Te3 with angle-resolved photoemission spectroscopy, we demonstrate that the surface state consists of a single nondegenerate Dirac cone. Furthermore, with appropriate hole doping, the Fermi level can be tuned to intersect only the surface states, indicating a full energy gap for the bulk states. Our results establish that Bi2Te3 is a simple model system for the three-dimensional topological insulator with a single Dirac cone on the surface. The large bulk gap of Bi2Te3 also points to promising potential for high-temperature spintronics applications.},
   author = {Y L Chen and J G Analytis and J H Chu and Z K Liu and S K Mo and X L Qi and H J Zhang and P H Lu and X Dai and Z Fang and S C Zhang and I R Fisher and Z Hussain and Z X Shen},
   doi = {10.1126/science.1173034},
   issn = {00368075},
   issue = {5937},
   journal = {Science},
   month = {10},
   pages = {178-181},
   pmid = {19520912},
   publisher = {American Association for the Advancement of Science},
   title = {Experimental realization of a three-dimensional topological insulator, Bi2Te3},
   volume = {325},
   year = {2009}
}
@article{Flammini2018,
   abstract = {We report a study of the interface between antimony and the prototypical topological insulator Bi 2 Se 3. Scanning tunnelling microscopy measurements show the presence of ordered domains displaying a perfect lattice match with bismuth selenide. Density functional theory calculations of the most stable atomic configurations demonstrate that the ordered domains can be attributed to stacks of β-antimonene.},
   author = {R Flammini and S Colonna and C Hogan and S K Mahatha and M Papagno and A Barla and P M Sheverdyaeva and P Moras and Z S Aliev and M B Babanly and E V Chulkov and C Carbone and F Ronci},
   doi = {10.1088/1361-6528/aaa2c4},
   journal = {Nanotechnology},
   keywords = {antimonene,antimony,bismuth selenide,density functional theory,scanning tunnelling microscopy,topological insulators},
   title = {Evidence of β-antimonene at the Sb/Bi 2 Se 3 interface},
   url = {https://doi.org/10.1088/1361-6528/aaa2c4},
   year = {2018}
}
@article{Moorsom2020,
   abstract = {We show that hybrid MnOx/C60 heterojunctions can be used to design a storage device for spin-polarized charge: a spin capacitor. Hybridization at the carbon-metal oxide interface leads to spin-polarized charge trapping after an applied voltage or photocurrent. Strong electronic structure changes, including a 1-eV energy shift and spin polarization in the C60 lowest unoccupied molecular orbital, are then revealed by x-ray absorption spectroscopy, in agreement with density functional theory simulations. Muon spin spectroscopy measurements give further independent evidence of local spin ordering and magnetic moments optically/electronically stored at the heterojunctions. These spin-polarized states dissipate when shorting the electrodes. The spin storage decay time is controlled by magnetic ordering at the interface, leading to coherence times of seconds to hours even at room temperature.},
   author = {T Moorsom and M Rogers and I Scivetti and S Bandaru and G Teobaldi and M Valvidares and M Flokstra and S Lee and R Stewart and T Prokscha and P Gargiani and N Alosaimi and G Stefanou and M Ali and F Al Ma'Mari and G Burnell and B J Hickey and O Cespedes},
   doi = {10.1126/sciadv.aax1085},
   issn = {23752548},
   issue = {12},
   journal = {Science Advances},
   month = {10},
   pages = {eaax1085},
   publisher = {American Association for the Advancement of Science},
   title = {Reversible spin storage in metal oxide-fullerene heterojunctions},
   volume = {6},
   year = {2020}
}
@article{Braun2009,
   abstract = {In this Review, we summarize recent work on modeling of organic/metal and organic/organic interfaces. Some of the models discussed have a semiempirical approach, that is, experimentally derived values are used in combination with theory, and others rely completely of calculations. The models are categorized according to the types of interfaces they apply to, and the strength of the interaction at the interface has been used as the main factor.We explain the basics of the models, their use, and give examples on how the models correlate with experimental results. We stress that given the complexity of organic/metal and organic/organic interface formation, it is crucial to know the exact way in which the interface was formed before choosing the model that is applicable, as none of the models presented covers the whole range of interface interaction strengths (weak physisorption to strong chemisorption). © 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.},
   author = {Slawomir Braun and William R Salaneck and Mats Fahlman},
   doi = {10.1002/adma.200802893},
   issn = {09359648},
   issue = {14-15},
   journal = {Advanced Materials},
   month = {10},
   pages = {1450-1472},
   title = {Energy-Level Alignment at Organic/Metal and Organic/Organic Interfaces},
   volume = {21},
   url = {http://doi.wiley.com/10.1002/adma.200802893},
   year = {2009}
}
@article{Dorset1994,
   abstract = {The crystal structure of C60 buckminsterfullerene was determined at room temperature by a direct phasing analysis of single-crystal electron-diffraction intensity data. The initial electrostatic potential map is well fit by a regular icosahedron of C atoms but with an average rotational disorder corresponding to Fm3m symmetry. The static appearance of this directly determined map, however, does not refute the notion of uncorrelated molecular positions in the crystal lattice, indicated earlier by nuclear-magnetic resonance spectroscopy and neutron scattering. Although the direct determination of crystallographic phases is correct, the occurrence of strong axial h00 reflections in the electron diffraction patterns appears to be a result of secondary scattering. Correction for this perturbation produces a good fit of the intensities to an isotropic spherical shell of C atoms. In fact, the static appearance of the initial potential map is artificial, owing to the use of only a limited set of phased structure factors in the Fourier transform carried out after the ab initio structure analysis.},
   author = {D L Dorset and M P McCourt},
   doi = {10.1107/S0108767393012607},
   issn = {16005724},
   issue = {3},
   journal = {Acta Crystallographica Section A},
   month = {10},
   pages = {344-351},
   publisher = {International Union of Crystallography},
   title = {Disorder and the molecular packing of C60 buckminsterfullerene: a direct electron‐crystallographic analysis},
   volume = {50},
   year = {1994}
}
@article{Pai2010,
   abstract = {We demonstrate the charge state of C60 on a Cu(111) surface can be made optimal, i.e., forming C603- as required for superconductivity in bulk alkali-doped C60, purely through interface reconstruction rather than with foreign dopants. We link the origin of the C603- charge state to a reconstructed interface with ordered (4×4) 7-atom vacancy holes in the surface. In contrast, C60 adsorbed on unreconstructed Cu(111) receives a much smaller amount of electrons. Our results illustrate a definitive interface effect that affects the electronic properties of molecule-electrode contact. © 2010 The American Physical Society.},
   author = {Woei Wu Pai and H T Jeng and C M Cheng and C H Lin and Xudong Xiao and Aidi Zhao and Xieqiu Zhang and Geng Xu and X Q Shi and M A Van Hove and C S Hsue and K D Tsuei},
   doi = {10.1103/PhysRevLett.104.036103},
   issn = {00319007},
   issue = {3},
   journal = {Physical Review Letters},
   month = {10},
   pages = {36103},
   publisher = {American Physical Society},
   title = {Optimal electron doping of a C60 monolayer on Cu(111) via interface reconstruction},
   volume = {104},
   year = {2010}
}
@article{Dodabalapur1995,
   abstract = {Organic field-effect transistors have been developed that function as either n-channel or p-channel devices, depending on the gate bias. The two active materials are α-hexathienylene (α-6T) and C60. The characteristics of these devices depend mainly on the molecular orbital energy levels and transport properties of α-6T and C60. The observed effects are not unique to the two materials chosen and can be quite universal provided certain conditions are met. The device can be used as a building block to form low-cost, low-power complementary integrated circuits.},
   author = {A Dodabalapur and H E Katz and L Torsi and R C Haddon},
   doi = {10.1126/science.269.5230.1560},
   issn = {00368075},
   issue = {5230},
   journal = {Science},
   month = {10},
   pages = {1560-1562},
   publisher = {American Association for the Advancement of Science},
   title = {Organic heterostructure field-effect transistors},
   volume = {269},
   year = {1995}
}
@article{S2020,
   author = {Krishtopenko S S. and Antezza M. and Teppe F.},
   doi = {10.1088/1361-648X/ab6741},
   journal = {Journal of Physics-Condensed Matter},
   title = {Hybridization of topological surface states with a flat band},
   url = {https://doi.org/10.1088/1361-648X/ab6741},
   year = {2020}
}
@article{Nakajima1963,
   abstract = {It has been confirmed that Bi2Te3 and Bi2Se3 form complete solid solutions, their space group being D53d-R3&#x0304;m. The unit cell dimensions for the specimens having various compositions are given. The atomic parameters are found to be u = 0.4000 and v = 0.2097 for Bi2Te3, u = 0.3958 and v = 0.2118 for Bi2Te2Se, u = 0.3985 and v = 0.2115 for Bi2TeSe2, and u = 0.4008 and v = 0.2117 for Bi2Se3. Two kinds of bond length for Bi-Te (Se) are found. They lie in a range between covalent and ionic extremes. The temperature factors of each atom are also estimated. Relations between the crystallographic data and physical properties are discussed. © 1963.},
   author = {Seizo Nakajima},
   doi = {10.1016/0022-3697(63)90207-5},
   issn = {00223697},
   issue = {3},
   journal = {Journal of Physics and Chemistry of Solids},
   month = {10},
   pages = {479-485},
   publisher = {Pergamon},
   title = {The crystal structure of Bi2Te3-xSex},
   volume = {24},
   year = {1963}
}
@article{Mal2019,
   abstract = {Herein, using Raman spectroscopy, we have presented the investigation of a temperature-dependent frequency shift and the line broadening of phonon modes by inserting the atomic layers of Pb and PbTe in the prototype 3D topological insulator Bi2Te3. Good quality single crystals of Pb2Bi2Te3, PbBi2Te4, and PbBi4Te7 were grown using the modified Bridgman technique. The Raman modes show progressive blue-shift with the decrease in temperature from 298 K to 93 K in Pb2Bi2Te3, PbBi2Te4, and PbBi4Te7 due to the anharmonic vibrations of the lattice as well as the increase in the strength of Bi-Te covalent interactions. The experimental results were complemented by extensive first principles calculations, where a reasonable matching between the experimental and computational data was found. Chemical pressure, induced by the insertion of Pb and PbTe layers in Bi2Te3, modified the interactions at the boundaries of the quintuple-layers, which was evident from the evolution of the A21u mode. The enhancement in the out-of-plane Bi-Te vibrations with respect to the in-plane Bi-Te vibrations was observed at low temperatures. The temperature coefficients of the Raman modes were useful in determining the thermal conductivity, which is a key design parameter for the fabrication of spintronic devices using topological insulators. The estimated first order temperature coefficient (χ′) for Pb2Bi2Te3 signified the decrease in the thermal conductivity relative to Bi2Te3, which was caused by the insertion of the Pb layers in the van der Waals gaps of Bi2Te3.},
   author = {Priyanath Mal and G Bera and G R Turpu and Sunil K Srivastava and A Gangan and Brahmananda Chakraborty and Bipul Das and Pradip Das},
   doi = {10.1039/c9cp01494b},
   issn = {14639076},
   issue = {27},
   journal = {Physical Chemistry Chemical Physics},
   month = {10},
   pages = {15030-15039},
   publisher = {Royal Society of Chemistry},
   title = {Vibrational spectra of Pb2Bi2Te3, PbBi2Te4, and PbBi4Te7 topological insulators: Temperature-dependent Raman and theoretical insights from DFT simulations},
   volume = {21},
   year = {2019}
}
@article{Deshpande2014,
   abstract = {We report here on Raman spectroscopic studies of Bi2Se 3 single crystal synthesized by chemical vapor transport technique as a function of pressure (0-12 GPa) and temperature (80-300 K). Polarized Raman experiments in the back-scattering configuration were performed to determine the position of the two dominant first-order Raman-active modes, Eg2 and A1g2 at around 132 and 174 cm-1 respectively. High pressure Raman measurements provides the evidence that Bi2Se3 single crystal undergoes first order phase transition above 10 GPa. Isobaric and isothermal mode Gruneisen parameter have been determined from the temperature and pressure dependent Raman spectra for both Raman active modes of Bi 2Se3 single crystal. The analysis of the experimental data showed that the temperature dependencies of the phonon frequencies and linewidths were well described by considering the contributions from thermal expansion and lattice anharmonicity. © 2013 Elsevier B.V.},
   author = {M P Deshpande and Sandip V Bhatt and Vasant Sathe and Rekha Rao and S H Chaki},
   doi = {10.1016/j.physb.2013.10.008},
   issn = {09214526},
   issue = {1},
   journal = {Physica B: Condensed Matter},
   keywords = {Anharmonic effects,Bi2Se3 single crystal,High pressure,Low temperature},
   month = {10},
   pages = {72-78},
   publisher = {North-Holland},
   title = {Pressure and temperature dependence of Raman spectra and their anharmonic effects in {Bi$_2$Se$_3$} single crystal},
   volume = {433},
   year = {2014}
}
@article{Yuan2015,
   abstract = {In this paper, we report a facile solvothermal method to produce both binary and ternary compounds of bismuth chalcogenides in the form of Bi2TexSe3-x. The crystal morphology in terms of geometry and thickness as well as the stoichiometric ratio can be well controlled, which offers the opportunities to systematically investigate the relationship between microstructure and phonon scattering by Raman spectroscopy. Raman spectra of four compounds, i.e., Bi2Se3, Bi2Se2Te, Bi2SeTe2 and Bi2Te3, were collected at four different excitation photon energies (2.54, 2.41, 1.96, and 1.58 eV). It is found that the vibrational modes are shifted to higher frequency with more Se incorporation towards the replacement of Te. The dependence of Raman vibrational modes on excitation photon energy was investigated. As the excitation photon energy increases, three Raman vibrational modes (A1g1, Eg2 and A1g2) of the as-produced compounds move to low frequency. Three Infrared-active (IR-active) modes were observed in thin topological insulators (TIs) crystals.},
   author = {Jian Yuan and Meng Zhao and Wengzhi Yu and Yao Lu and Caiyun Chen and Meng Xu and Shaojuan Li and Kian Loh and Bao Qiaoliang},
   doi = {10.3390/ma8085007},
   issn = {1996-1944},
   issue = {8},
   journal = {Materials},
   keywords = {Bismuth chalcogenide,Infrared active,Raman spectroscopy,Solvothermal,Stoichiometric ratio},
   month = {10},
   pages = {5007-5017},
   publisher = {MDPI AG},
   title = {Raman Spectroscopy of Two-Dimensional {Bi$_2$Te$_x$Se$_{3−x}$} Platelets Produced by Solvothermal Method},
   volume = {8},
   url = {http://www.mdpi.com/1996-1944/8/8/5007},
   year = {2015}
}
@article{Park2015,
   abstract = {Single-crystal Bi 2 Te 3 nanowires (NWs) and nanoribbons (NRs) were synthesized by a vapor-liquid-solid (VLS) method from Bi 2 Te 3 powder. To investigate the thermal properties of the Bi 2 Te 3 nanostructure, a nondestructive technique based on temperature dependent Raman mapping was carried out. The Raman peaks were red shifted with increasing temperature. In addition, the fraction of the laser power absorbed inside the Bi 2 Te 3 nanostructures was estimated by optical simulation and used to calculate the thermal conductivity value (κ). The thermal conductivity value obtained for the Bi 2 Te 3 NW and NR was 1.47 Wm −1 K −1 and 1.81 Wm −1 K −1 at 300 K, respectively. The electrical conductivity of the Bi 2 Te 3 nanostructure was also measured. In particular, an excellent electrical conductivity value of 1.22 * 10 3 Ω −1 cm −1 was obtained for the Bi 2 Te 3 NW at 300 K. This result can be attributed to topological insulator surface states. As a result of our study, the figure of merit (ZT) for the Bi 2 Te 3 NW and NR can be significantly improved. Thermoelectric (TE) devices have recently attracted a great deal of interest because of their potential applications in energy harvesting, chip cooling and sensing. Thermoelectric (TE) power generation devices play an important role in utilizing solar and geothermal power more efficiently, as well as in capturing automobile-derived heat via a noise-free and low-maintenance conversion process 1-3. In order to use TE devices in such applications, attaining a high efficiency is the most important issue. Therefore, many studies have been made in attempts to obtain a high efficiency through the development of new materials and device modification 4-7. Thermoelectric performance is typically evaluated by a dimensionless figure of merit (ZT), defined as ZT = S 2 σ T/κ , where S is the Seebeck coefficient, σ is electrical conductivity, T is absolute temperature, and κ is thermal conductivity 8. To improve the figure of merit, the three factors, namely the simultaneous increase in electrical conductivity, increasing thermoelectric power, and decreasing thermal conductivity need to be controlled. In order to achieve a conversion efficiency by replacing the general cooling-generation technology a ZT of 4 is needed. However, at present, ZT = 2 represents the practical limit for conventional structure and materials. Therefore, recent studies have focused on reducing the dimensionality of typical materials into the nanoscale range because both a higher density of states and an increased phonon scattering or reduced lattice thermal conductivity can be achieved in low-dimensional structures 9. Bi 2 Te 3 is a well-known material that can be used as a semiconductor, given its low lattice thermal conductivity and, simultaneously, a quite high electrical conductivity. Therefore, it has been actively studied in attempts to increase the ZT value through reducing the dimensions into a nano structure. In the measurement of thermal conductivity in nanostructures, the 3-omega method is generally used. However, the sample is destroyed during the measurement, which makes device fabrication difficult 10-12. Moreover, thermal contact resistance is a critical problem in terms of extracting the intrinsic thermal conductivity using nearly all of the steady-state heat flow methods. Therefore, noncontact approaches using optical spectroscopy have been introduced to measure the thermal conductivity of individual semiconductor nanowires (NW) 13-15 , nanotubes 16 , any layered structures such as MoS 2 17 and graphene 18. This method is based on the heat},
   author = {Dambi Park and Sungjin Park and Kwangsik Jeong and Hong-Sik Jeong and Jea Yong Song and Mann-Ho Cho},
   doi = {10.1038/srep19132},
   journal = {Nature Publishing Group},
   title = {Thermal and Electrical Conduction of Single-crystal Bi 2 Te 3 Nanostructures grown using a one step process OPEN},
   url = {www.nature.com/scientificreports},
   year = {2015}
}
@article{German2019,
   abstract = {The tetradymite compound BiSbTeSe2 is one of the most bulk-insulating three-dimensional topological insulators, which makes it important in topological insulator research. It is a member of the solid-solution system Bi2-xSbxTe3-ySey, for which the local crystal structure, such as the occupation probabilities of each atomic site, is not well understood. We have investigated the temperature- and polarization-dependent spontaneous Raman scattering in BiSbTeSe2, revealing a much higher number of lattice vibrational modes than predicted by group-theoretical considerations for the space group R3m corresponding to an ideally random solid-solution situation. The density-functional calculations of phonon frequencies show a very good agreement with experimental data for parent material Bi2Te3, where no disorder effects were found. In comparison to Bi2Te3 the stacking disorder in BiSbTeSe2 causes a discrepancy between theory and experiment. Combined analysis of experimental Raman spectra and density-functional-theory-calculated phonon spectra for different types of atomic orders showed coexistence of different sequences of layers in the material and that those with Se in the center and a local order of Se-Bi-Se-Sb-Te are the most favored.},
   author = {Raphael German and Evgenia V Komleva and Philipp Stein and Vladimir G Mazurenko and Zhiwei Wang and Sergey V Streltsov and Yoichi Ando and Paul H M Van Loosdrecht},
   doi = {10.1103/PhysRevMaterials.3.054204},
   issn = {24759953},
   issue = {5},
   journal = {Physical Review Materials},
   month = {10},
   pages = {54204},
   publisher = {American Physical Society},
   title = {Phonon mode calculations and Raman spectroscopy of the bulk-insulating topological insulator {BiSbTeSe$_2$}},
   volume = {3},
   year = {2019}
}
@article{Tian2016,
   abstract = {Local modes caused by defects play a significant role in the thermal transport properties of thermoelectrics. Of particular interest are charge-neutral defects that suppress thermal conductivity, without significantly reducing electrical transport. Here, we report a temperature dependent Raman study that identifies such a mode in a standard thermoelectric material, Bi2Te2Se. One of the modes observed, whose origin has been debated for decades, was shown most likely to be an antisite defect induced local mode. The anomalous temperature independent broadening of the local mode is ascribed to the random arrangement of Se atoms. The temperature renormalization of all modes is well explained by an anharmonic model-Klemens's model.},
   author = {Yao Tian and Gavin B Osterhoudt and Shuang Jia and R J Cava and Kenneth S Burch},
   doi = {10.1063/1.4941022},
   issn = {00036951},
   issue = {4},
   journal = {Applied Physics Letters},
   keywords = {Raman spectra,antisite defects,bismuth compounds,localised modes,phonons,renormalisation,semiconductor materials,tellurium compounds,thermal conductivity,thermoelectricity},
   month = {10},
   pages = {41911},
   publisher = {American Institute of Physics Inc.},
   title = {Local phonon mode in thermoelectric Bi2Te2Se from charge neutral antisites},
   volume = {108},
   url = {http://aip.scitation.org/doi/10.1063/1.4941022},
   year = {2016}
}
@article{Balkanski1983,
   abstract = {Systematic measurements by light scattering of the linewidth and frequency shift of the q=0 optical phonon in silicon over the temperature range of 5-1400 K are presented. Both the linewidth and frequency shift exhibit a quadratic dependence on temperature at high temperatures. This indicates the necessity of including terms in the phonon proper self-energy corresponding to four-phonon anharmonic processes. © 1983 The American Physical Society.},
   author = {M Balkanski and R F Wallis and E Haro},
   doi = {10.1103/PhysRevB.28.1928},
   issn = {01631829},
   issue = {4},
   journal = {Physical Review B},
   month = {10},
   pages = {1928-1934},
   publisher = {American Physical Society},
   title = {Anharmonic effects in light scattering due to optical phonons in silicon},
   volume = {28},
   year = {1983}
}
@article{Kim2016,
   abstract = {Raman spectra of few-layer MoSe2 were measured with eight excitation energies. New peaks that appear only near resonance with various exciton states are analyzed, and the modes are assigned. The resonance profiles of the Raman peaks reflect the joint density of states for optical transitions, but the symmetry of the exciton wave functions leads to selective enhancement of the A1g mode at the A exciton energy and the shear mode at the C exciton energy. We also find Davydov splitting of intralayer A1g, E1g, and A2u modes due to interlayer interaction for some excitation energies near resonances. Furthermore, by fitting the spectral positions of interlayer shear and breathing modes and Davydov splitting of intralayer modes to a linear chain model, we extract the strength of the interlayer interaction. We find that the second-nearest-neighbor interlayer interaction amounts to about 30% of the nearest-neighbor interaction for both in-plane and out-of-plane vibrations.},
   author = {Kangwon Kim and Jae Ung Lee and Dahyun Nam and Hyeonsik Cheong},
   doi = {10.1021/acsnano.6b04471},
   issn = {1936086X},
   issue = {8},
   journal = {ACS Nano},
   keywords = {Davydov splitting,MoSe2,Raman spectroscopy,excitonic resonance,molybdenum diselenide},
   month = {10},
   pages = {8113-8120},
   publisher = {American Chemical Society},
   title = {Davydov Splitting and Excitonic Resonance Effects in Raman Spectra of Few-Layer MoSe2},
   volume = {10},
   year = {2016}
}
@article{Kullmann1990,
   abstract = {The extremely anisotropic bonding properties of the narrow gap semiconductor bismuth telluride (Bi2Te3) with sandwich structure is studied by inelastic neutron scattering. In combination with lattice dynamical shell model calculations, new information is obtained on the complex bonding forces of this sandwich structured V–VI semiconductor. The sandwich character leads predominantely to three‐dimensional bonding behavior. No characteristic two‐dimensional lattice properties can be observed. Copyright © 1990 WILEY‐VCH Verlag GmbH & Co. KGaA},
   author = {W Kullmann and G Eichhorn and H Rauh and R Geick and G Eckold and U Steigenberger},
   doi = {10.1002/pssb.2221620109},
   issn = {03701972},
   issue = {1},
   journal = {physica status solidi (b)},
   month = {10},
   pages = {125-140},
   title = {Lattice Dynamics and Phonon Dispersion in the Narrow Gap Semiconductor Bi2Te3 with Sandwich Structure},
   volume = {162},
   url = {http://doi.wiley.com/10.1002/pssb.2221620109},
   year = {1990}
}
@article{Richter1977,
   abstract = {The Raman‐active lattice vibrations of Bi2Se3, Bi2Te3, Sb2Te3, and their solid slutions, whose symmetries correspond to the R3m space group, are investigated by Raman scattering. Three of the four expected Raman modes, Eg and A1g, could be determined. The FIR optical properties of Bi2Te3 crystal surfaces of improved quality (E ∥ c and E ⟂ c) and Bi2Se3 (E ⟂ c) are re‐examined near helium and room temperature with a Fourier spectrometer, allowing a determination of the infrared‐active mode frequencies with higher accuracy. The results for Bi2Te3 are compared to the predicted frequencies from the lattice dynamical model, given by Jenkins et al. The frequncy shifts of the Raman‐active modes in the mixed crystals show single‐mode and two‐mode behaviour, which is in agreement with simple models for the substitution of antimony and selenium atoms for bismuth and tellurium, respectively, in Bi2Te3. Copyright © 1977 WILEY‐VCH Verlag GmbH & Co. KGaA},
   author = {W Richter and C R Becker},
   doi = {10.1002/pssb.2220840226},
   issn = {03701972},
   issue = {2},
   journal = {Physica Status Solidi (b)},
   month = {10},
   pages = {619-628},
   title = {A Raman and far-infrared investigation of phonons in the rhombohedral {V$_2$–VI$_3$ compounds $B$i$_2$$T$e$_3$, $B$i$_2$$S$e$_3$, $S$b$_2$Te$_3$ and Bi$_2$(Te$_{1−x}$Se$_x$)$_3$, (Bi$_{1−y}$Sb$_y$)$_2$Te$_3$}},
   volume = {84},
   url = {http://doi.wiley.com/10.1002/pssb.2220840226},
   year = {1977}
}
@article{Liu2019,
   abstract = {We investigate the anharmonic effects in Bi2Se3 crystals using femtosecond transient optical spectroscopy at 5-280 K. The reflectivity time series consist of exponential decay due to hot carriers and decaying oscillations due to the A 1 g 1 phonon vibration. Vibration frequency and dephasing time of this optical phonon mode are obtained as a function of temperature, decreasing with increasing temperature; both the red shift in frequency and the increased dephasing rate induced by heating can be well described using the anharmonicity model including lattice thermal expansion and phonon-phonon coupling.},
   author = {Qiya Liu and Ruihui Shao and Ning Li and Weizheng Liang and Xinsheng Yang and S N Luo and Yong Zhao},
   doi = {10.1063/1.5131257},
   issn = {00036951},
   issue = {20},
   journal = {Applied Physics Letters},
   month = {10},
   pages = {201902},
   publisher = {American Institute of Physics Inc.},
   title = {Anharmonicity of Bi2Se3 revealed by fs transient optical spectroscopy},
   volume = {115},
   url = {http://aip.scitation.org/doi/10.1063/1.5131257},
   year = {2019}
}
@article{Gervais1997,
   abstract = {The crucial role of electron-phonon interactions and their signatures in optical conductivity deduced from the analysis of infrared-visible reflection spectra is reviewed. The usefulness of a general phenomenological model able to describe the couplings of phonons, polarons, plasmon, superconducting condensate, is discussed. Among other exam3les of applications, the problem of the signature of Cooper wir condensation in the superconducting phase of highTc cuprates is discussed in the framework of London and Uattis-Bardeen models. © Springer-Verlag 1997.},
   author = {François Gervais and Ricardo Lobo},
   doi = {10.1007/s002570050508},
   issn = {07223277},
   issue = {4},
   journal = {Zeitschrift fur Physik B-Condensed Matter},
   keywords = {Condensed Matter Physics,Engineering,Inorganic Chemistry,general},
   month = {10},
   pages = {681-686},
   publisher = {Springer Verlag},
   title = {Infrared reflectivity spectroscopy of electron-phonon interactions},
   volume = {104},
   year = {1997}
}
@article{Laforge2010,
   abstract = {We present an infrared magneto-optical study of the highly thermoelectric narrow-gap semiconductor Bi2 Se3. Far-infrared and midinfrared (IR) reflectance and transmission measurements have been performed in magnetic fields oriented both parallel and perpendicular to the trigonal c axis of this layered material and supplemented with UV-visible ellipsometry to obtain the optical conductivity σ1 (ω). With lowering of temperature we observe narrowing of the Drude conductivity due to reduced quasiparticle scattering, as well as an increase in the absorption edge due to direct electronic transitions. Magnetic fields H?c dramatically renormalize and asymmetrically broaden the strongest far-IR optical phonon, indicating interaction of the phonon with the continuum free-carrier spectrum and significant magnetoelectric coupling. For the perpendicular field orientation, electronic absorption is enhanced, and the plasma edge is slightly shifted to higher energies. In both cases the direct transition energy is softened in magnetic field. © 2010 The American Physical Society.},
   author = {A D Laforge and A Frenzel and B C Pursley and Tao Lin and Xinfei Liu and Jing Shi and D N Basov},
   doi = {10.1103/PhysRevB.81.125120},
   issn = {10980121},
   issue = {12},
   journal = {Physical Review B - Condensed Matter and Materials Physics},
   month = {10},
   pages = {125120},
   publisher = {American Physical Society},
   title = {Optical characterization of Bi2Se3 in a magnetic field: Infrared evidence for magnetoelectric coupling in a topological insulator material},
   volume = {81},
   year = {2010}
}
@article{Verble1970,
   abstract = {The observed degeneracy of mutually exclusive infrared- and Raman-active modes in MoS2 is traced by means of group theory to the weak van der Waals interaction between layers. © 1970 The American Physical Society.},
   author = {J L Verble and T J Wieting},
   doi = {10.1103/PhysRevLett.25.362},
   issn = {00319007},
   issue = {6},
   journal = {Physical Review Letters},
   month = {10},
   pages = {362-365},
   publisher = {American Physical Society},
   title = {Lattice mode degeneracy in MoS2 and other layer compounds},
   volume = {25},
   year = {1970}
}
@article{Chen2011,
   abstract = {Lattice constant of Bi 2Se 3 and Sb 2Te 3 crystals is determined by x-ray powder diffraction measurement in a wide temperature range. Linear thermal expansion coefficients (α) of the crystals are extracted, and considerable anisotropy between α ∥ and α ⊥ is observed. The low temperature values of α can be fit well by the Debye model, while an anomalous behavior at above 150 K is evidenced and explained. Grneisen parameters of the materials are also estimated at room temperature. © 2011 American Institute of Physics.},
   author = {X Chen and H D Zhou and A Kiswandhi and I Miotkowski and Y P Chen and P A Sharma and A L Lima Sharma and M A Hekmaty and D Smirnov and Z Jiang},
   doi = {10.1063/1.3672198},
   issn = {00036951},
   issue = {26},
   journal = {Applied Physics Letters},
   keywords = {Gruneisen coefficient,X-ray diffraction,antimony compounds,bismuth compounds,lattice constants,thermal expansion},
   month = {10},
   pages = {261912},
   publisher = {American Institute of PhysicsAIP},
   title = {Thermal expansion coefficients of {Bi$_2$ Se$_3$} and {Sb$_2$ Te$_3$} crystals from 10 K to 270 K},
   volume = {99},
   url = {http://aip.scitation.org/doi/10.1063/1.3672198},
   year = {2011}
}
@article{Jenkins1972,
   abstract = {The six independent elastic moduli of Bi2 Te3 have been measured from 4.2 to 300 K using a continuous-wave resonance technique. Extrapolation of the measurements to absolute zero gives C11=7.436, C66=2.619, C33=5.160, C44=3.135, C13=2.917, and C14=1.541 in units of 1011 dyn/cm2. These values correspond to a limiting Debye temperature of 164.9 ± 0.2 K, which agrees with the calorimetric value of 165 ± 2 K. A Born-von Kármán lattice model providing for central and angular forces between first and second neighbors is constructed to fit the moduli. Using the model, the frequencies of infrared absorption and Raman scattering are predicted and the density of phonon states and lattice specific heat are found. The calculated specific heat differs appreciably from the calorimetric measurements, indicating the possible importance of third- and fourth-neighbor interactions. © 1972 The American Physical Society.},
   author = {J O Jenkins and J A Rayne and R W Ure},
   doi = {10.1103/PhysRevB.5.3171},
   issn = {01631829},
   issue = {8},
   journal = {Physical Review B},
   month = {10},
   pages = {3171-3184},
   publisher = {American Physical Society},
   title = {Elastic moduli and phonon properties of Bi2 Te3},
   volume = {5},
   year = {1972}
}
@article{Kamaraju2010,
   author = {N Kamaraju and Sunil Kumar and A K Sood},
   doi = {10.1209/0295-5075/92/47007},
   issn = {0295-5075},
   issue = {4},
   journal = {EPL (Europhysics Letters)},
   month = {10},
   pages = {47007},
   publisher = {IOP Publishing},
   title = {Temperature-dependent chirped coherent phonon dynamics in Bi2Te3 using high-intensity femtosecond laser pulses},
   volume = {92},
   year = {2010}
}
@article{Shahil2012,
   abstract = {Bismuth telluride (Bi 2Te 3) and related compounds have recently attracted strong interest, owing to the discovery of the topological insulator properties in many members of this family of materials. The few-quintuple films of these materials are particularly interesting from the physics point of view. We report results of the micro-Raman spectroscopy study of the "graphene-like" exfoliated few-quintuple layers of Bi 2Te 3, Bi 2Se 3, and Sb 2Te 3. It is found that crystal symmetry breaking in few-quintuple films results in appearance of A 1u-symmetry Raman peaks, which are not active in the bulk crystals. The scattering spectra measured under the 633-nm wavelength excitation reveals a number of resonant features, which could be used for analysis of the electronic and phonon processes in these materials. In order to elucidate the influence of substrates on the few-quintuple-thick topological insulators, we examined the Raman spectra of these films placed on mica, sapphire, and hafnium-oxide substrates. The obtained results help to understand the physical mechanisms of Raman scattering in the few-quintuple-thick films and can be used for nanometrology of topological insulator films on various substrates. © 2012 American Institute of Physics.},
   author = {K M F Shahil and M Z Hossain and V Goyal and A A Balandin},
   doi = {10.1063/1.3690913},
   issn = {00218979},
   issue = {5},
   journal = {Journal of Applied Physics},
   keywords = {Raman spectra,antimony compounds,bismuth compounds,crystal symmetry,multilayers,topological insulators},
   month = {10},
   pages = {54305},
   publisher = {American Institute of PhysicsAIP},
   title = {Micro-Raman spectroscopy of mechanically exfoliated few-quintuple layers of Bi 2Te 3, Bi 2Se 3, and Sb 2Te 3 materials},
   volume = {111},
   url = {http://aip.scitation.org/doi/10.1063/1.3690913},
   year = {2012}
}
@article{Srgers1994,
   abstract = {Niobium films with constant thickness have been deposited on sapphire (1120) by electron-beam evaporation at different substrate temperatures (150 °C ≤TS ≤ 750 °C). The samples were characterized by X-ray diffraction and resistivity measurements. X-ray reflectivity shows that all films are covered with an oxide layer of about 20 Å in ambient atmosphere. The (110) texture at high TS decreases towards lower TS, accompanied by an increasing surface roughness. Below TS = 350 °C the grain size in the growth direction becomes smaller than the film thickness and a relaxation of intrinsic stress is observed. A transition from a columnar growth structure to a fine grained microstructure is inferred. The change of the microstructure with TS is probably due to the temperature dependent grain boundary mobility during the deposition process. © 1994.},
   author = {C Sürgers and C Strunk and H v. Löhneysen},
   doi = {10.1016/0040-6090(94)90107-4},
   issn = {00406090},
   issue = {1},
   journal = {Thin Solid Films},
   month = {10},
   pages = {51-56},
   publisher = {Elsevier},
   title = {Effect of substrate temperature on the microstructure of thin niobium films},
   volume = {239},
   year = {1994}
}
@article{Allen1977,
   abstract = {The two-dimensional plasmon of an n inversion layer of (100) p-type Si is observed at a fixed wave vector as a function of electron density. The position, width, and strength of the resonance agree with existing theory at electron densities 1012/cm2. At lower densities, the resonance position is below the predicted value, implying a substantial increase in the electron mass. © 1977 The American Physical Society.},
   author = {S J Allen and D C Tsui and R A Logan},
   doi = {10.1103/PhysRevLett.38.980},
   issn = {00319007},
   issue = {17},
   journal = {Physical Review Letters},
   month = {10},
   pages = {980-983},
   publisher = {American Physical Society},
   title = {Observation of the two-dimensional plasmon in silicon inversion layers},
   volume = {38},
   year = {1977}
}
@article{Cinchetti2017,
   abstract = {H erbert Kroemer famously wrote in his Nobel lecture of 2000, "the interface is the device" 1. Although he was referring to the continuous miniaturization and complexity increase pursued by the semiconductor industry, his statement can certainly be applied to related research and technology areas, such as magnetism and spintronics. In the past couple of decades or so, these have been among the main players in the new revolution of interfacial electronics. One of the most celebrated results in spin transport is the preferential tunnelling in Fe/MgO magnetic tunnel junctions, which constitutes one of the pillars of modern magnetic recording 2. This effect is very much a consequence of new properties emerging at the interface, rather than directly from the bulk of each of the independent constituent materials. More recent examples of phenomenology appearing at interfaces are spin-orbit-related phenomena 3 , such as the spin-to-charge conversion due to the Rashba-Edelstein effect 4,5 and the spin-momentum locking at the surface of topological insulating materials 6. In this Perspective, we describe how molecular materials have arisen as an ideal platform for creating interfacial spin effects and discuss the key role that molecular interfaces may play in the development of a new generation of spin-based technologies, thanks to their unique capability of being actively tuned to reach as-yet unex-plored functionalities. Research in molecular spintronics began with the aim of using molecules as spin transport media, thanks to their intrinsically weak spin relaxation mechanisms 7. Initial experiments focused on reaching spin transport in molecular films and on replicating previous device concepts taken from inorganic spintronics, such as spin valves 8-12 (Fig. 1a) and magnetic tunnel junctions 13-15. However, it soon became apparent that molecules were playing another role beyond that of mere spin transport materials. For example, in experiments with vertical spin valves, many groups were reporting consistently negative magnetoresistance 16-18. These results were striking, as they contradicted the well-established spin polarization sign of the ferromagnetic electrodes and the present knowledge at that time regarding spin transport 13. A few years later, a coherent picture arose invoking the role of molecular layers in tuning the spin polarization of ferromagnetic The miniaturization trend in the semiconductor industry has led to the understanding that interfacial properties are crucial for device behaviour. Spintronics has not been alien to this trend, and phenomena such as preferential spin tunnelling, the spin-to-charge conversion due to the Rashba-Edelstein effect and the spin-momentum locking at the surface of topological insulators have arisen mainly from emergent interfacial properties, rather than the bulk of the constituent materials. In this Perspective we explore inorganic/molecular interfaces by looking closely at both sides of the interface. We describe recent developments and discuss the interface as an ideal platform for creating new spin effects. Finally, we outline possible technologies that can be generated thanks to the unique active tunability of molecular spinterfaces. for example, refs 21-24), as these are fundamental in several other areas with intense technological development, such as molecular optoelectronics 25. Early studies focused on the need to understand charge transport at metal/molecular interfaces. Accordingly, they gathered information on the energy level alignment at the interface, which is the energy barrier for carrier injection from the Fermi level of a metal into the highest occupied molecular orbital (HOMO) or lowest unoccupied molecular orbital (LUMO) levels of a molecular material 21. Subsequent studies presented a more refined understanding of the energetics of molecular interfaces by, for instance, developing concepts such as energy level broadening or polaronic effects 23. Although the energetics of molecular interfaces is a wide and complex topic slightly beyond the scope of this Perspective, we would like nevertheless to highlight some aspects that are relevant for interfacial spintronics 26,27. The molecule-substrate interaction on inert surfaces such as gold is determined by weak van der Waals forces in a regime usually called physisorption. In this case, the molecular orbitals are similar to those of the gas phase and are virtually not affected by the substrate 28,29. A wider phenomenol-ogy occurs on more reactive metal surfaces, such as those of fer-romagnetic metals, as in this case the interactions at the interface may lead to the formation of chemical bonds between the molecular adsorbates and the substrate. The strength of the interaction is measured by ΔE, defined as the difference between, on one side, the energy of the separate molecular entities and the metal substrate, and, on the other, the energy of the hybrid system. Values of ΔE larger than 1 eV set the boundary for the regime commonly known as chemisorption 30. A basic understanding of the chemical adsorption of organic molecules on metal surfaces can be achieved under the Newns-Anderson model 31,32 (see Box 1). The crucial parameters in this model are the bandwidth of the metal bands (W) and the hybridi-zation strength (ΔE). On sp metal surfaces, such as Ag and Cu, the large bandwidth of the sp bands (around 10 eV) typically leads to W/ΔE >> 1. This is the regime of weak chemisorption, as observed, for example, at the Ag/perylenetetracarboxylic dianhydride (PTCDA) interface 29,33. In electron photoemission experiments, the LUMO of PTCDA is typically observed below the Fermi level as a consequence of the partial charge transfer accompanying the chemical bond. In addition, the molecular level is broadened into an interface resonance lying energetically within the sp bands of Ag. © 2 0 1 7 M a c m i l l a n P u b l i s h e r s L i m i t e d , p a r t o f S p r i n g e r N a t u r e. A l l r i g h t s r e s e r v e d .},
   author = {Mirko Cinchetti and V Alek Dediu and Luis E Hueso},
   doi = {10.1038/NMAT4902},
   journal = {NATURE MATERIALS |},
   pages = {25},
   title = {Activating the molecular spinterface},
   volume = {16},
   url = {www.nature.com/naturematerials},
   year = {2017}
}
@article{Jakobs2015,
   abstract = {We present a rational design approach to customize the spin texture of surface states of a topological insulator. This approach relies on the extreme multifunctionality of organic molecules that are used to functionalize the surface of the prototypical topological insulator (TI) Bi<inf>2</inf>Se<inf>3</inf>. For the rational design we use theoretical calculations to guide the choice and chemical synthesis of appropriate molecules that customize the spin texture of Bi<inf>2</inf>Se<inf>3</inf>. The theoretical predictions are then verified in angular-resolved photoemission experiments. We show that, by tuning the strength of molecule-TI interaction, the surface of the TI can be passivated, the Dirac point can energetically be shifted at will, and Rashba-split quantum-well interface states can be created. These tailored interface properties-passivation, spin-texture tuning, and creation of hybrid interface states-lay a solid foundation for interface-assisted molecular spintronics in spin-textured materials.},
   author = {Sebastian Jakobs and Awadhesh Narayan and Benjamin Stadtmüller and Andrea Droghetti and Ivan Rungger and Yew S Hor and Svetlana Klyatskaya and Dominik Jungkenn and Johannes Stöckl and Martin Laux and Oliver L A Monti and Martin Aeschlimann and Robert J Cava and Mario Ruben and Stefan Mathias and Stefano Sanvito and Mirko Cinchetti},
   doi = {10.1021/acs.nanolett.5b02213},
   issn = {15306992},
   issue = {9},
   journal = {Nano Letters},
   keywords = {Topological insulators,hybrid organic/inorganic interfaces,organic molecules,spin texture},
   month = {10},
   pages = {6022-6029},
   publisher = {American Chemical Society},
   title = {Controlling the Spin Texture of Topological Insulators by Rational Design of Organic Molecules},
   volume = {15},
   year = {2015}
}
@misc{Ford1984,
   author = {G W Ford and W H Weber},
   doi = {10.1016/0370-1573(84)90098-X},
   issn = {03701573},
   issue = {4},
   journal = {Physics Reports},
   month = {10},
   pages = {195-287},
   publisher = {North-Holland},
   title = {Electromagnetic interactions of molecules with metal surfaces},
   volume = {113},
   year = {1984}
}
@article{Zhang2012,
   abstract = {We analyze the results of scanning near-field infrared spectroscopy performed on thin films of a-SiO 2 on Si substrate. The measured near-field signal exhibits surface-phonon resonances whose strength has a prominent thickness dependence in the range from 2 to 300nm. These observations are compared with calculations in which the tip of the near-field infrared spectrometer is modeled either as a point dipole or an elongated spheroid. The latter model accounts for the antenna effect of the tip and gives a better agreement with the experiment. Possible applications of the near-field technique for depth profiling of layered nanostructures are discussed. © 2012 American Physical Society.},
   author = {L M Zhang and G O Andreev and Z Fei and A S McLeod and G Dominguez and M Thiemens and A H Castro-Neto and D N Basov and M M Fogler},
   doi = {10.1103/PhysRevB.85.075419},
   issn = {10980121},
   issue = {7},
   journal = {Physical Review B - Condensed Matter and Materials Physics},
   month = {10},
   pages = {75419},
   publisher = {American Physical Society},
   title = {Near-field spectroscopy of silicon dioxide thin films},
   volume = {85},
   url = {https://journals.aps.org/prb/abstract/10.1103/PhysRevB.85.075419},
   year = {2012}
}
@article{Fei2011,
   abstract = {We report on infrared (IR) nanoscopy of 2D plasmon excitations of Dirac fermions in graphene. This is achieved by confining mid-IR radiation at the apex of a nanoscale tip: an approach yielding 2 orders of magnitude increase in the value of in-plane component of incident wavevector q compared to free space propagation. At these high wavevectors, the Dirac plasmon is found to dramatically enhance the near-field interaction with mid-IR surface phonons of SiO2 substrate. Our data augmented by detailed modeling establish graphene as a new medium supporting plasmonic effects that can be controlled by gate voltage. © 2011 American Chemical Society.},
   author = {Zhe Fei and Gregory O Andreev and Wenzhong Bao and Lingfeng M Zhang and Alexander S McLeod and Chen Wang and Margaret K Stewart and Zeng Zhao and Gerardo Dominguez and Mark Thiemens and Michael M Fogler and Michael J Tauber and Antonio H Castro-Neto and Chun Ning Lau and Fritz Keilmann and Dimitri N Basov},
   doi = {10.1021/nl202362d},
   issn = {15306984},
   issue = {11},
   journal = {Nano Letters},
   keywords = {Dirac plasmon,Graphene,infrared nanoscopy,near-field microscopy},
   month = {10},
   pages = {4701-4705},
   pmid = {21972938},
   publisher = {American Chemical Society},
   title = {Infrared nanoscopy of dirac plasmons at the graphene-SiO2 interface},
   volume = {11},
   url = {https://pubs.acs.org/sharingguidelines},
   year = {2011}
}
@article{Drabble1958,
   abstract = {A model for the chemical bondins in bismuth telluride is proposed which appears to dispose of some of the difficulties involved in earlier models. The new model is used to explain some of the properties of bismuth telluride and of its alloys with bismuth selenide. © 1958.},
   author = {J R Drabble and C H L Goodman},
   doi = {10.1016/0022-3697(58)90139-2},
   issn = {0022-3697},
   issue = {1-2},
   journal = {Journal of Physics and Chemistry of Solids},
   month = {10},
   pages = {142-144},
   publisher = {Pergamon},
   title = {Chemical bonding in bismuth telluride},
   volume = {5},
   year = {1958}
}
@article{Schreyeck2016,
   abstract = {We study the chemical ordering in Bi2Te3-xSex grown by molecular beam epitaxy on Si substrates. We produce films in the full composition range from x = 0 to 3, and determine their material properties using energy dispersive x-ray spectroscopy, x-ray diffraction and Raman spectroscopy. By fitting the parameters of a kinetic growth model to these results, we obtain a consistent description of growth at a microscopic level. Our main finding is that despite the incorporation of Se in the central layer being much more probable than that of Te, the formation of a fully ordered Te-Bi-Se-Bi-Te layer is prevented by kinetic of the growth process. Indeed, the Se concentration in the central layer of Bi2Te2Se1 reaches a maximum of only ≈75% even under ideal growth conditions. A second finding of our work is that the intensity ratio of the 0 0 12 and 0 0 6 x-ray reflections serves as an experimentally accessible quantitative measure of the degree of ordering in these films.},
   author = {S Schreyeck and K Brunner and A Kirchner and U Bass and S Grauer and C Schumacher and C Gould and G Karczewski and J Geurts and L W Molenkamp},
   doi = {10.1088/0953-8984/28/14/145002},
   issn = {0953-8984},
   issue = {14},
   journal = {Journal of Physics: Condensed Matter},
   keywords = {bismuth telluride selenide alloy,chemical order,epitaxy,growth model,topological insulator},
   month = {10},
   pages = {145002},
   publisher = {IOP Publishing},
   title = {Kinetic limitation of chemical ordering in {Bi$_2$Te$_{3−x}$Se$_x$} layers grown by molecular beam epitaxy},
   volume = {28},
   url = {https://iopscience.iop.org/article/10.1088/0953-8984/28/14/145002 https://iopscience.iop.org/article/10.1088/0953-8984/28/14/145002/meta},
   year = {2016}
}
@article{Akrap2012,
   abstract = {The temperature dependence of the complex optical properties of the three-dimensional topological insulator Bi2Te2Se is reported for light polarized in the a-b planes at ambient pressure, as well as the effects of pressure at room temperature. This material displays a semiconducting character with a bulk optical gap of Eg300 meV at 295 K. In addition to the two expected infrared-active vibrations observed in the planes, there is an additional fine structure that is attributed to either the removal of degeneracy or the activation of Raman modes due to disorder. A strong impurity band located at 200 cm-1 is also observed. At and just above the optical gap, several interband absorptions are found to show a strong temperature and pressure dependence. As the temperature is lowered these features increase in strength and harden. The application of pressure leads to a very abrupt closing of the gap above 8 GPa, and strongly modifies the interband absorptions in the midinfrared spectral range. While ab initio calculations fail to predict the collapse of the gap, they do successfully describe the size of the band gap at ambient pressure, and the magnitude and shape of the optical conductivity. © 2012 American Physical Society.},
   author = {Ana Akrap and Michaël Tran and Alberto Ubaldini and Jérémie Teyssier and Enrico Giannini and Dirk Van Der Marel and Philippe Lerch and Christopher C Homes},
   issue = {23},
   journal = {Physical Review B - Condensed Matter and Materials Physics},
   month = {10},
   title = {Optical properties of {Bi$_2$Te$_2$Se} at ambient and high pressures},
   volume = {86},
   year = {2012}
}
@article{Pietro2013,
   abstract = {Plasmons are quantized collective oscillations of electrons and have been observed in metals and doped semiconductors. The plasmons of ordinary, massive electrons have been the basic ingredients of research in plasmonics and in optical metamaterials for a long time1. However, plasmons of massless Dirac electrons have only recently been observed in graphene, a purely two-dimensional electron system2. Their properties are promising for novel tunable plasmonic metamaterials in the terahertz and mid-infrared frequency range3. Dirac fermions also occur in the two-dimensional electron gas that forms at the surface of topological insulators as a result of the strong spin–orbit interaction existing in the insulating bulk phase4. One may therefore look for their collective excitations using infrared spectroscopy. Here we report the first experimental evidence of plasmonic excitations in a topological insulator (Bi2Se3). The material was prepared in thin micro-ribbon arrays of different widths W and periods 2W to select suitable values of the plasmon wavevector k. The linewidth of the plasmon was found to remain nearly constant at temperatures between 6 K and 300 K, as expected when exciting topological carriers. Moreover, by changing W and measuring the plasmon frequency in the terahertz range versus k we show, without using any fitting parameter, that the dispersion curve agrees quantitatively with that predicted for Dirac plasmons. Plasmonic excitation of massless electrons is observed in Bi2Se3.},
   author = {P Di Pietro and M Ortolani and O Limaj and A Di Gaspare and V Giliberti and F Giorgianni and M Brahlek and N Bansal and N Koirala and S Oh and P Calvani and S Lupi},
   doi = {10.1038/nnano.2013.134},
   issn = {1748-3395},
   issue = {8},
   journal = {Nature Nanotechnology 2013 8:8},
   keywords = {Electronic properties and materials,Metamaterials},
   month = {10},
   pages = {556-560},
   publisher = {Nature Publishing Group},
   title = {Observation of Dirac plasmons in a topological insulator},
   volume = {8},
   url = {https://www.nature.com/articles/nnano.2013.134},
   year = {2013}
}
@article{Wu2013,
   abstract = {The quantum phase transition from a topological to a conventional insulator in In-doped Bi2Se3 occurs when the topological phase is destroyed by the hybridization of states on opposite surfaces. This is characterized by a sudden change in the transport lifetime, measured by means of optical spectroscopy. Topological insulators are newly discovered states of matter with robust metallic surface states protected by the topological properties of the bulk wavefunctions1,2,3,4,5,6. A quantum phase transition from a topological insulator to a conventional insulator and a change in topological class can occur only when the bulk bandgap closes3. In this work, we have used time-domain terahertz spectroscopy to investigate the low-frequency conductance in (Bi1−xInx)2Se3 as we tune through this transition by In substitution. Above certain substitution levels we observe a collapse in the transport lifetime that indicates the destruction of the topological phase. We associate this effect with the threshold where states from opposite surfaces hybridize. The substitution level of the threshold is thickness dependent and only asymptotically approaches the bulk limit x≈0.06 where a maximum in the mid-infrared absorption is exhibited. This absorption can be identified with the bulk bandgap closing and change in topological class. The correlation length associated with the quantum phase transition appears as the evanescent length of the surface states. The observation of the thickness-dependent collapse of the transport lifetime shows the unusual role that finite-size effects play in this topological quantum phase transition.},
   author = {Liang Wu and M Brahlek and R Valdés Aguilar and A V Stier and C M Morris and Y Lubashevsky and L S Bilbro and N Bansal and S Oh and N P Armitage},
   doi = {10.1038/nphys2647},
   issn = {1745-2481},
   issue = {7},
   journal = {Nature Physics 2013 9:7},
   keywords = {Topological matter},
   month = {10},
   pages = {410-414},
   publisher = {Nature Publishing Group},
   title = {A sudden collapse in the transport lifetime across the topological phase transition in {(Bi$_{1−x}$In$_x$)$_2$Se$_3$}},
   volume = {9},
   url = {https://www.nature.com/articles/nphys2647},
   year = {2013}
}
@article{Khanikaev2016,
   abstract = {We investigate the propagation of surface plasmon polaritons (SPPs) in thin films of topological insulators. Cases of single films and multilayered stacks are analyzed. The materials considered are second generation three dimensional topological insulators Bi2Se3, Bi2Te3, and Sb2Te3. Dispersion relations and propagation lengths of SPPs are estimated numerically, taking into account the variation of bulk dielectric functions of topological insulators, as well as substrate, using the Drude-Lorentz model. The key factors affecting propagation length are identified and experimental modifications for tuning the dispersion relations are proposed. The apparent discrepancy between the experimental data and previously considered theory is resolved.},
   author = {Alexander Khanikaev and Jacob Trevino and Lia Krusin-Elbaum and Vinod Menon and Yury Deshko},
   doi = {10.1364/OE.24.007398},
   issn = {1094-4087},
   issue = {7},
   journal = {Optics Express, Vol. 24, Issue 7, pp. 7398-7410},
   keywords = {Optical materials,Optical superlattices,Quantum cascade semiconductor lasers,Quantum computing,Surface plasmon polaritons,Thin films},
   month = {10},
   pages = {7398-7410},
   publisher = {Optical Society of America},
   title = {Surface plasmon polaritons in topological insulator nano-films and superlattices},
   volume = {24},
   url = {https://www.osapublishing.org/viewmedia.cfm?uri=oe-24-7-7398&seq=0&html=true https://www.osapublishing.org/abstract.cfm?uri=oe-24-7-7398 https://www.osapublishing.org/oe/abstract.cfm?uri=oe-24-7-7398},
   year = {2016}
}
@article{Soni2012,
   abstract = {We report on the enhanced thermoelectric properties of selenium (Se) doped bismuth telluride (Bi2Te3–xSex) nanoplatelet (NP) composites synthesized by the polyol method. Variation of the Se composi...},
   author = {Ajay Soni and Zhao Yanyuan and Yu Ligen and Michael Khor Khiam Aik and Mildred S Dresselhaus and Qihua Xiong},
   doi = {10.1021/NL2034859},
   issue = {3},
   journal = {Nano Letters},
   keywords = {Bi2Te3−xSex nanoplatelets,Thermoelectric figure of merit,energy filtering,nanocomposites,polyol synthesis},
   month = {10},
   pages = {1203-1209},
   publisher = {American Chemical Society},
   title = {Enhanced Thermoelectric Properties of Solution Grown Bi$_2$Te$_{3–x}$Se$_x$ Nanoplatelet Composites},
   volume = {12},
   url = {https://pubs.acs.org/doi/abs/10.1021/nl2034859},
   year = {2012}
}
@article{Wieder1974,
   abstract = {Heteroepitaxially grown single‐crystal InAs layers exhibit anomalies in the magnetic field dependence of their Hall coefficients, their magnetoresistance, and the temperature dependence of their el...},
   author = {H H Wieder},
   doi = {10.1063/1.1655441},
   issn = {0003-6951},
   issue = {4},
   journal = {Applied Physics Letters},
   month = {10},
   pages = {206},
   publisher = {American Institute of PhysicsAIP},
   title = {Transport coefficients of {InAs} epilayers},
   volume = {25},
   url = {https://aip.scitation.org/doi/abs/10.1063/1.1655441},
   year = {1974}
}
@article{K2014,
   abstract = {Topological insulators represent a novel state of matter with surface charge carriers having a massless Dirac dispersion and locked helical spin polarization. Many exciting experiments have been proposed by theory, yet their execution has been hampered by the extrinsic conductivity associated with the unavoidable presence of defects in Bi2Te3 and Bi2Se3 bulk single crystals, as well as impurities on their surfaces. Here we present the preparation of Bi2Te3 thin films that are insulating in the bulk and the fourpoint probe measurement of the conductivity of the Dirac states on surfaces that are intrinsically clean. The total amount of charge carriers in the experiment is of the order of 1012 cm-2 only, and mobilities up to 4,600 cm2/Vs have been observed. These values are achieved by carrying out the preparation, structural characterization, angle-resolved and X-ray photoemission analysis, and tem-perature-dependent four-point probe conductivity measurement all in situ under ultra-high-vacuum conditions. This experimental approach opens the way to prepare devices that can exploit the intrinsic topological properties of the Dirac surface states.},
   author = {Hoefer K and Becker C and Rata D and Swanson J and Thalmeier P and Tjeng LH},
   doi = {10.1073/PNAS.1410591111},
   issn = {0027-8424},
   issue = {42},
   journal = {Proceedings of the National Academy of Sciences of the United States of America},
   keywords = {Dirac Electrons,Europe PMC,Europe PubMed Central,In Situ Four-point Conductance,Molecular Beam Epitaxy,ORCIDs,REST APIs,Thin Films,Topological Insulator,abstracts,bioinformatics,biological patents,biomedical journals,biomedical research,citation networks,citation search,clinical guidelines,full text,journal articles,life sciences,literature search,open access,research articles,text mining},
   month = {10},
   pages = {14979-14984},
   pmid = {25294928},
   publisher = {National Academy of Sciences},
   title = {Intrinsic conduction through topological surface states of insulating Bi2Te3 epitaxial thin films.},
   volume = {111},
   url = {https://europepmc.org/articles/PMC4210329 https://europepmc.org/article/med/25294928},
   year = {2014}
}
@article{Butch2010,
   abstract = {While evidence of a topologically nontrivial surface state has been identified in surface-sensitive measurements of Bi2 Se3, a significant experimental concern is that no signatures have been observed in bulk transport. In a search for such states, nominally undoped single crystals of Bi2 Se3 with carrier densities approaching 1016 cm-3 and very high mobilities exceeding 2- m2 V-1s-1 have been studied. A comprehensive analysis of Shubnikov-de Haas oscillations, Hall effect, and optical reflectivity indicates that the measured electrical transport can be attributed solely to bulk states, even at 50 mK at low Landau-level filling factor, and in the quantum limit. The absence of a significant surface contribution to bulk conduction demonstrates that even in very clean samples, the surface mobility is lower than that of the bulk, despite its topological protection. © 2010 The American Physical Society.},
   author = {N P Butch and K Kirshenbaum and P Syers and A B Sushkov and G S Jenkins and H D Drew and J Paglione},
   doi = {10.1103/PhysRevB.81.241301},
   issue = {24},
   journal = {Physical Review B},
   month = {10},
   pages = {241301},
   publisher = {American Physical Society},
   title = {Strong surface scattering in ultrahigh-mobility {Bi$_2$Se$_3$} topological insulator crystals},
   volume = {81},
   url = {https://journals.aps.org/prb/abstract/10.1103/PhysRevB.81.241301},
   year = {2010}
}
@article{Gan2018,
   abstract = {We adopted and extended an efficient Grüneisen formalism to study the phonon anharmonicity and linear thermal expansion coefficients (TECs) of trigonal bismuth selenide (Bi2Se3) and antimony telluride (Sb2Te3). Anharmonicity of the systems is studied via extensive calculation of Grüneisen parameters that exploit symmetry-preserving deformations. Consistent with experimental findings, a large anisotropy between the TECs in the a and c directions is found. The larger anharmonicity inherent in Sb2Te3, as compared to Bi2Se3 is offset by the volumetric effect, resulting in comparable temperature dependence of their linear TECs. The Debye temperatures deduced from our first-principles data also agree very well with the existing tabulated values. The highly efficient methodology developed in this work, applied for the first time to study the linear TECs of two trigonal thermoelectric systems, opens up exciting opportunities to address the anharmonic effects in other thermoelectrics and other low-symmetry materials.},
   author = {Chee Kwan Gan and Ching Hua Lee},
   doi = {10.1016/J.COMMATSCI.2018.04.036},
   issn = {0927-0256},
   journal = {Computational Materials Science},
   keywords = {Antimony telluride,Bismuth selenide,Debye temperature,Grüneisen parameter,Phonon calculations,Thermal expansion,Thermoelectric materials,Topological insulators},
   month = {10},
   pages = {49-52},
   publisher = {Elsevier},
   title = {Anharmonic phonon effects on linear thermal expansion of trigonal bismuth selenide and antimony telluride crystals},
   volume = {151},
   year = {2018}
}
@article{Ren2010,
   abstract = {Topological insulators are predicted to present interesting surface transport phenomena but their experimental studies have been hindered by a metallic bulk conduction that overwhelms the surface transport. We show that the topological insulator Bi2 Te2 Se presents a high resistivity exceeding 1Ωcm and a variable-range hopping behavior, and yet presents Shubnikov-de Haas oscillations coming from the topological surface state. Furthermore, we have been able to clarify both the bulk and surface transport channels, establishing a comprehensive understanding of the transport in this material. Our results demonstrate that Bi2 Te2 Se is, to our knowledge, the best material to date for studying the surface quantum transport in a topological insulator. © 2010 The American Physical Society.},
   author = {Zhi Ren and A A Taskin and Satoshi Sasaki and Kouji Segawa and Yoichi Ando},
   doi = {10.1103/PhysRevB.82.241306},
   issue = {24},
   journal = {Physical Review B},
   month = {10},
   pages = {241306},
   publisher = {American Physical Society},
   title = {Large bulk resistivity and surface quantum oscillations in the topological insulator <span class},
   volume = {82},
   url = {https://journals.aps.org/prb/abstract/10.1103/PhysRevB.82.241306},
   year = {2010}
}
@article{Hegde2020,
   abstract = {Polycrystalline samples of (Bi1-xInx)2Se2.7Te0.3 (x = 0.00, 0.02, and 0.04) were prepared by the solid-state reaction technique. X-ray diffraction pattern confirms that the polycrystalline samples have a hexagonal structure with spacegroup R 



{-}{3}

m. The surface morphologic study reveals the existence of porous behavior in the studied samples due to the volatilization of Selenium. Energy dispersive X-ray analysis validates the expected and observed elemental composition of the samples. Electrical resistivity has shown metallic behavior. Hall effect and Seebeck coefficient measurements indicate the p-type and n-type conduction for the pristine sample Bi2Se3 and the (Bi1-xInx)2Se2.7Te0.3 samples, respectively. The thermal conductivity and electrical resistivity were found to reduce by 7.5 and 9 times, respectively, for (Bi0.96In0.04)2Se2.7Te0.3 compared to the pristine sample Bi2Se3.},
   author = {Ganesh Shridhar Hegde and A N Prabhu and R Y Huang and Y K Kuo},
   doi = {10.1007/S10854-020-04383-7},
   issn = {1573-482X},
   issue = {22},
   journal = {Journal of Materials Science: Materials in Electronics 2020 31:22},
   keywords = {Characterization and Evaluation of Materials,Optical and Electronic Materials},
   month = {10},
   pages = {19511-19525},
   publisher = {Springer},
   title = {Reduction in thermal conductivity and electrical resistivity of indium and tellurium co-doped bismuth selenide thermoelectric system},
   volume = {31},
   url = {https://link.springer.com/article/10.1007/s10854-020-04383-7},
   year = {2020}
}
@article{Yao2017,
   abstract = {We use a magnetothermal resistance method to measure the lattice thermal conductivity of single-crystal Bi2Te3 from 5 to 60 K. Lattice thermal conductivity is calculated by extrapolating the thermal conductivity versus electrical conductivity curve to a zero electrical conductivity value. Our results show that the measured phonon thermal conductivity follows the temperature dependence and the Lorenz ratio corresponds to the modified Sommerfeld value in the intermediate temperature range. Our low-temperature experimental data and analysis on Bi2Te3 are a complement to previous measurements of Goldsmid (Ref. 17) and theoretical calculations by Hellman et al. (Ref. 18) at higher temperature 100–300 K.},
   author = {Mengliang Yao and Cyril Opeil and Stephen Wilson and Mona Zebarjadi},
   doi = {10.1557/MRC.2017.118},
   issn = {2159-6859},
   issue = {4},
   journal = {MRS Communications},
   month = {10},
   pages = {922-927},
   publisher = {Cambridge University Press},
   title = {Experimental determination of phonon thermal conductivity and Lorenz ratio of single-crystal bismuth telluride},
   volume = {7},
   url = {https://www.cambridge.org/core/journals/mrs-communications/article/experimental-determination-of-phonon-thermal-conductivity-and-lorenz-ratio-of-singlecrystal-bismuth-telluride/ECEDF1471EA2C69FA7BDDDB39BFFCA7E},
   year = {2017}
}
@article{Shukla2003,
   abstract = {We measure phonon dispersion and linewidth in a single crystal of [Formula presented] along the [Formula presented], [Formula presented], and [Formula presented] directions using inelastic x-ray scattering. We use density functional theory to compute the effect of both electron-phonon coupling and anharmonicity on the linewidth, obtaining excellent agreement with experiment. Anomalous broadening of the [Formula presented] phonon mode is found all along [Formula presented]. The dominant contribution to the linewidth is always the electron-phonon coupling. © 2003 The American Physical Society.},
   author = {Abhay Shukla and Matteo Calandra and Matteo d’Astuto and Michele Lazzeri and Francesco Mauri and Christophe Bellin and Michael Krisch and J Karpinski and S M Kazakov and J Jun and D Daghero and K Parlinski},
   doi = {10.1103/PhysRevLett.90.095506},
   issue = {9},
   journal = {Physical Review Letters},
   month = {10},
   pages = {95506},
   publisher = {American Physical Society},
   title = {Phonon Dispersion and Lifetimes in {MgB$_2$}},
   volume = {90},
   url = {https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.90.095506},
   year = {2003}
}
@article{Heid2017,
   abstract = {The use of topological edge states for spintronic applications could be severely hampered by limited lifetimes due to intrinsic many-body interactions, in particular electron-phonon coupling. Previous works to determine the intrinsic coupling strength did not provide a coherent answer. Here, the electron-phonon interaction in the metallic surface state of 3D topological insulators is revised within a first principles framework. For the archetypical cases of Bi2Se3 and Bi2Te3, we find an overall weak coupling constant of less than 0.15, but with a characteristic energy dependence. Derived electronic self-energies compare favorably with previous angle-resolved photoemission spectroscopy results. The prevailing coupling is carried by optical modes of polar character, which is weakly screened by the metallic surface state and can be reduced by doping into bulk bands. We do not find any indication of a strong coupling to the A1g mode or the presence of a Kohn anomaly in the surface phonon spectrum. The weak intrinsic electron-phonon coupling guarantees long-lived quasiparticles at elevated temperatures.},
   author = {Rolf Heid and Irina Yu Sklyadneva and Evgueni V Chulkov},
   issue = {1},
   journal = {Scientific Reports},
   month = {10},
   publisher = {Nature Publishing Group},
   title = {Electron-phonon coupling in topological surface states: The role of polar optical modes},
   volume = {7},
   year = {2017}
}
@article{Wagner1978,
   abstract = {The dispersion curves for phonons propagating along the trigonal axis of the layer‐structure emiconductor Bi2Te3 at 77 K have been determined by coherent inelastic neutron scattering techniques. Analysis of these results in terms of a simple interplanar force model shows a) that the forces between adjacent planes of Te atoms are comparable to those between nearest neighbour planes of Bi and Te and b) that foreces between next‐nearest‐neighbour planes have to be considered. In addition, a limited number of phonons were measured at 300 K and some low‐frequency modes propagating along the bisectrix within the planes were determind. The results are compared, where possible, with previous Raman scattering, infrared reflection, and elastic constant measurements. Copyright © 1978 WILEY‐VCH Verlag GmbH & Co. KGaA},
   author = {V Wagner and G Dolling and B M Powell and G Landwehr},
   doi = {10.1002/PSSB.2220850134},
   issn = {1521-3951},
   issue = {1},
   journal = {physica status solidi (b)},
   month = {10},
   pages = {311-317},
   publisher = {John Wiley \& Sons, Ltd},
   title = {Lattice vibrations of {Bi$_2$Te$_3$}},
   volume = {85},
   url = {https://onlinelibrary.wiley.com/doi/full/10.1002/pssb.2220850134 https://onlinelibrary.wiley.com/doi/abs/10.1002/pssb.2220850134 https://onlinelibrary.wiley.com/doi/10.1002/pssb.2220850134},
   year = {1978}
}
@article{Chen2013,
   abstract = {Three-dimensional topological insulators are characterized by insulating bulk state and metallic surface state involving relativistic Dirac fermions which are responsible for exotic quantum phenomena and potential applications in spintronics and quantum computations. It is essential to understand how the Dirac fermions interact with other electrons, phonons and disorders. Here we report super-high resolution angle-resolved photoemission studies on the Dirac fermion dynamics in the prototypical Bi2(Te,Se)3 topological insulators. We have directly revealed signatures of the electron-phonon coupling and found that the electron-disorder interaction dominates the scattering process. The Dirac fermion dynamics in Bi2(Te3−xSex) topological insulators can be tuned by varying the composition, x, or by controlling the charge carriers. Our findings provide crucial information in understanding and engineering the electron dynamics of the Dirac fermions for fundamental studies and potential applications.},
   author = {Chaoyu Chen and Zhuojin Xie and Ya Feng and Hemian Yi and Aiji Liang and Shaolong He and Daixiang Mou and Junfeng He and Yingying Peng and Xu Liu and Yan Liu and Lin Zhao and Guodong Liu and Xiaoli Dong and Jun Zhang and Li Yu and Xiaoyang Wang and Qinjun Peng and Zhimin Wang and Shenjin Zhang and Feng Yang and Chuangtian Chen and Zuyan Xu and X J Zhou},
   doi = {10.1038/srep02411},
   issn = {2045-2322},
   issue = {1},
   journal = {Scientific Reports 2013 3:1},
   keywords = {Electronic devices,Electronic properties and materials,Spintronics,Topological matter},
   month = {10},
   pages = {1-6},
   publisher = {Nature Publishing Group},
   title = {Tunable Dirac Fermion Dynamics in Topological Insulators},
   volume = {3},
   url = {https://www.nature.com/articles/srep02411},
   year = {2013}
}
@article{Buchenau2020,
   abstract = {We have investigated two-dimensional nanostructures of the topological insulators Bi2Se3 and Bi2Te3 by means of temperature and magnetic field dependent Raman spectroscopy. The surface contribution of our samples was increased by using thin films of dropcasted nanoflakes with the aim of enhancing their topological properties. Raman spectroscopy provides a contact-free method to investigate the behavior of topological properties with temperature and magnetic fields at lower dimensions. The temperature dependent Raman study reveals anharmonic phonon behavior for Bi2Te3 indicative of a two-phonon relaxation mechanism in this material. Contrary to this, Bi2Se3 shows clear deviations from a two-phonon anharmonic decay model at temperatures below 120 K exhibiting a hardening and broadening, especially of the A1g2 mode. Similarly, the magnetic field dependent self-energy effects are only observed for the A1g2 mode of Bi2Se3, showing a broadening and hardening with increasing field. We interpret our results in terms of corrections to the phonon self-energy for Bi2Se3 at temperatures below 120 K and magnetic fields above 4 T due to electron-hole pair excitations associated with the conducting surface states. The phonon renormalization with increasing magnetic field is explained by a gap opening in the Dirac cone that enables phonon coupling to the changing electric susceptibility.},
   author = {Sören Buchenau and Sarah Scheitz and Astha Sethi and John E Slimak and Tomke Eva Glier and Pranab Kumar Das and Torben Dankwort and Lewis Akinsinde and Lorenz Kienle and Andrivo Rusydi and Clemens Ulrich and S Lance Cooper and Michael Rübhausen},
   doi = {10.1103/PhysRevB.101.245431},
   issue = {24},
   journal = {Physical Review B},
   month = {10},
   pages = {245431},
   publisher = {American Physical Society},
   title = {Temperature and magnetic field dependent Raman study of electron-phonon interactions in thin films of {Bi$_2$Se$_3$} and {Bi$_2$Te$_3$} nanoflakes},
   volume = {101},
   url = {https://journals-aps-org.eu1.proxy.openathens.net/prb/abstract/10.1103/PhysRevB.101.245431},
   year = {2020}
}
@article{Krewer2018,
   abstract = {We present a new approach for accurate terahertz time-domain spectroscopy of thin films deposited on dielectric substrates. Our approach relies on the simultaneous measurement of film and substrate, allowing for 15 nm—precise determination of the thickness variation between the sample and reference. Our approach allows for unprecedentedly accurate determination of the terahertz conductivity of the thin film. We demonstrate our approach on a 10 nm thin iron film deposited on a 500 μm MgO substrate. We determine the Drude momentum relaxation time in iron to within 0.15 fs uncertainty.},
   author = {Keno L Krewer and Zoltan Mics and Jacek Arabski and Guy Schmerber and Eric Beaurepaire and Mischa Bonn and Dmitry Turchinovich},
   doi = {10.1364/OL.43.000447},
   issn = {1539-4794},
   issue = {3},
   journal = {Optics Letters, Vol. 43, Issue 3, pp. 447-450},
   keywords = {Optical depth,Physical vapor deposition,Refractive index,Terahertz spectroscopy,Thin films,Ti:sapphire lasers},
   month = {10},
   pages = {447-450},
   publisher = {Optical Society of America},
   title = {Accurate terahertz spectroscopy of supported thin films by precise substrate thickness correction},
   volume = {43},
   url = {https://www.osapublishing.org/viewmedia.cfm?uri=ol-43-3-447&seq=0&html=true https://www.osapublishing.org/abstract.cfm?uri=ol-43-3-447 https://www.osapublishing.org/ol/abstract.cfm?uri=ol-43-3-447},
   year = {2018}
}
@article{Haki2019,
   abstract = {The electronic surface state of a three-dimensional strong topological insulator (TI) is characterized by an isotropic Dirac cone at the Γ point and an ideally perpendicular spin-momentum locking. Away from this point, the lattice anisotropy becomes effective where deviations from the ideal picture are observed. In particular, weak violations of the spin-momentum orthogonality is observed in many experiments. In parallel to these, the existence of the electron-phonon interaction has been verified by a number of experimental groups. In this article we devise an interacting theory of the surface spin. We observe that the interactions, while weakly affecting the energy bands, can yield changes in the spin texture in the presence of a Fermi surface anisotropy. In particular, using the coupling of a specific optical phonon experimentally discovered in the Bi2-ySbySe3-xTex family to the surface state, we obtain a sixfold nonorthogonal modulations in the in-plane spin-momentum pair. The out-of-plane spin experiments are also discussed in this context. Our results indicate that there is an additionally new mechanism contributing to the deviations in the spin texture beyond the conventional independent particle picture in topological materials where interactions are observed to be important. Recent experimental reports on the spin-momentum nonorthogonality in other symmetries, and even in nearly isotropic Fermi surfaces, indicate that the theory introduced here may be relevant to a larger set of interacting Dirac materials and deserves further exploration.},
   author = {T. Hakioğlu},
   doi = {10.1103/PhysRevB.100.165407},
   issue = {16},
   journal = {Physical Review B},
   month = {10},
   pages = {165407},
   publisher = {American Physical Society},
   title = {Effect of the electron-phonon interaction on the spin texture in {Bi$_{2-y}$Sb$_y$Se$_{3-x}$Te$_x$}},
   volume = {100},
   url = {https://journals.aps.org/prb/abstract/10.1103/PhysRevB.100.165407},
   year = {2019}
}
@article{Shekar2019,
   abstract = {Fast electrons interacting with matter have been instrumental for probing bulk and surface photonic excitations including Cherenkov radiation and plasmons. Additionally, fast electrons are ideal to investigate unique bulk and longitudinal photonic modes in hyperbolic materials at large wavevectors difficult to probe optically. Here, we use momentum-resolved electron energy loss spectroscopy (k-EELS) to perform the first experimental demonstration of high-k modes and hyperbolic Cherenkov radiation in the natural hyperbolic material Bi2Te3. This work establishes Bi2Te3 as one of the few viable natural hyperbolic materials in the visible and paves the way for k-EELS as a fundamental tool to probe hyperbolic media.},
   author = {Prashant Shekhar and Sarang Pendharker and Douglas Vick and Marek Malac and Zubin Jacob},
   doi = {10.1364/OE.27.006970},
   issn = {1094-4087},
   issue = {5},
   journal = {Optics Express, Vol. 27, Issue 5, pp. 6970-6975},
   keywords = {Blue shift,Electromagnetic radiation,Electrons,Extreme ultraviolet,Phase velocity,Surface plasmons},
   month = {3},
   pages = {6970-6975},
   publisher = {Optical Society of America},
   title = {Fast electrons interacting with a natural hyperbolic medium: bismuth telluride},
   volume = {27},
   url = {https://www.osapublishing.org/viewmedia.cfm?uri=oe-27-5-6970&seq=0&html=true https://www.osapublishing.org/abstract.cfm?uri=oe-27-5-6970 https://www.osapublishing.org/oe/abstract.cfm?uri=oe-27-5-6970},
   year = {2019}
}
@article{Tung2016,
   abstract = {We report a systematic study on the structural and electronic properties of Bi2Te3-xSex topological insulator alloy grown by molecular beam epitaxy (MBE). A mixing ratio of Bi2Se3 to Bi2Te3 was controlled by varying the Bi:Te:Se flux ratio. X-ray diffraction and Raman spectroscopy measurements indicate the high crystalline quality for the as-grown Bi2Te3-xSex films. Substitution of Te by Se is also revealed from both analyses. The surfaces of the films exhibit terrace-like quintuple layers and their size of the characteristic triangular terraces decreases monotonically with increasing Se content. However, the triangular terrace structure gradually recovers as the Se content further increases. Most importantly, the angle-resolved photoemission spectroscopy results provide evidence of single-Dirac-cone like surface states in which Bi2Te3-xSex with Se/Te-substitution leads to tunable surface states. Our results demonstrate that by fine-tuned MBE growth conditions, Bi2Te3-xSex thin film alloys with tunable topological surface states can be obtained, providing an excellent platform for exploring the novel device applications based on this compound.},
   author = {Y. Tung and Y. F. Chiang and C. W. Chong and Z. X. Deng and Y. C. Chen and J. C.A. Huang and C. M. Cheng and T. W. Pi and K. D. Tsuei and Z. Li and H. Qiu},
   issue = {5},
   journal = {Journal of Applied Physics},
   month = {2},
   publisher = {American Institute of Physics Inc.},
   title = {Growth and characterization of molecular beam epitaxy-grown {Bi$_2$Te$_{3-x}$Se$_x$} topological insulator alloys},
   volume = {119},
   year = {2016}
}
@article{Stauber2017,
   abstract = {We demonstrate via three examples that topological insulators (TI) offer a new platform for plasmonics. First, we show that the collective excitations of a thin slab of a TI display spin–charge sep...},
   author = {Tobias Stauber and Guillermo Gómez-Santos and Luis Brey},
   doi = {10.1021/ACSPHOTONICS.7B00524},
   issue = {12},
   journal = {ACS Photonics},
   keywords = {plasmons,spin−charge separation,topological insulators},
   month = {12},
   pages = {2978-2988},
   publisher = {American Chemical Society},
   title = {Plasmonics in Topological Insulators: Spin–Charge Separation, the Influence of the Inversion Layer, and Phonon–Plasmon Coupling},
   volume = {4},
   url = {https://pubs.acs.org/doi/abs/10.1021/acsphotonics.7b00524},
   year = {2017}
}
@article{Wu2015,
   abstract = {We present a theoretical analysis showing that layered topological insulators, for example, Bi2Se3 are optically hyperbolic materials in the range of terahertz (THz) frequencies. As such, these topological insulators possess deeply subdiffractional, highly directional collective modes: hyperbolic phonon polaritons. We predict that in thin crystals the dispersion of these modes is split into discrete subbands and is strongly influenced by electron surface states. If the surface states are doped, then hybrid collective modes result from coupling of the phonon polaritons with surface plasmons. The strength of the hybridization can be controlled by an external gate that varies the chemical potential of the surface states. We also show that the momentum dependence of the plasmon-phonon coupling leads to a polaritonic analog of the Goos-Hänchen effect. The directionality of the polaritonic rays and their tunable Goos-Hänchen shift is observable via THz nanoimaging.},
   author = {Jhih-Sheng Wu and D. N. Basov and M. M. Fogler},
   doi = {10.1103/PhysRevB.92.205430},
   issue = {20},
   journal = {Physical Review B},
   month = {11},
   pages = {205430},
   publisher = {American Physical Society},
   title = {Topological insulators are tunable waveguides for hyperbolic polaritons},
   volume = {92},
   url = {https://journals.aps.org/prb/abstract/10.1103/PhysRevB.92.205430},
   year = {2015}
}
@article{Singh2020,
   abstract = {Anharmonicity related to crystal structures strongly affects the phonon propagation and reduces lattice thermal conductivity (κl). Associated with a higher order of anharmonicity, thermoelectric (T...},
   author = {Niraj Kumar Singh and Ajay Soni},
   doi = {10.1063/5.0024651},
   issn = {0003-6951},
   issue = {12},
   journal = {Applied Physics Letters},
   month = {9},
   pages = {123901},
   publisher = { AIP Publishing LLC AIP Publishing },
   title = {Crystalline anharmonicity and ultralow thermal conductivity in layered Bi2GeTe4 for thermoelectric applications},
   volume = {117},
   url = {https://aip.scitation.org/doi/abs/10.1063/5.0024651},
   year = {2020}
}
@article{Wang2013,
   abstract = {Thermal properties and transport control are important for many applications, for example, low thermal conductivity is desirable for thermoelectrics. Knowledge of modewise phonon properties is crucial to identify dominant phonon modes for thermal transport and to design effective phonon barriers for thermal transport control. In this paper, we adopt time-domain (TD) and frequency-domain (FD) normal-mode analyses to investigate mode-wise phonon properties and to calculate phonon dispersion relations and phonon relaxation times in bismuth telluride. Our simulation results agree with the previously reported data obtained from ultrafast time-resolved measurements. By combining frequency-dependent anharmonic phonon group velocities and lifetimes, mode-wise thermal conductivities are predicted to reveal the contributions of heat carriers with different wavelengths and polarizations. Copyright © 2013 by ASME.},
   author = {Yaguo Wang and Bo Qiu and Alan J.H. McGaughey and Xiulin Ruan and Xianfan Xu},
   issn = {00221481},
   issue = {9},
   journal = {Journal of Heat Transfer},
   keywords = {Bismuth telluride,Phonon dispersion,Phonon lifetime,Thermal conductivity},
   month = {9},
   publisher = {American Society of Mechanical Engineers Digital Collection},
   title = {Mode-wise thermal conductivity of Bismuth Telluride},
   volume = {135},
   year = {2013}
}
@article{Jeon2019,
   author = {Hyeon-Gu Jeon and Jae Yong Song},
   doi = {10.1088/1361-6463/ab2f3a},
   title = {Capturing anharmonic and anisotropic natures in the thermotics and mechanics of Bi 2 Te 3 thermoelectric material through an accurate and efficient potential},
   url = {https://doi.org/10.1088/1361-6463/ab2f3a},
   year = {2019}
}
@article{Huang2019,
   abstract = {Force-field-(FF)-based molecular simulation is essential but challenging in the theoretical research of complex thermoelectric (TE) materials. As they are general and crucial in TE semiconductors, the structural natures of anharmonicity and anisotropy can help us understand the inherent relation between thermal and mechanical behavior, and therefore the reliability of FF studies can be assessed. In this paper, given prior knowledge of the structural, mechanical and thermal properties as well as the limitations and necessary approximations of the FF method, a feasible and detailed FF modeling scheme and simulation has been designed for Bi2Te3, which is a typical high-performance TE material. Using the complementary approach combining quasi-harmonic lattice and molecular dynamics, the obtained potential is systematically confirmed to be accurate and efficient for the prediction of anharmonic and anisotropic behavior in thermotics and mechanics over a wide temperature range compared with the present Bi2Te3 models. This reveals that the intrinsic anisotropy and anharmonicity can measure the asymmetry of crystal lattices and the interatomic force in the current state. In addition, the significant distinction of temperature-dependent anharmonic effects in different directions of Bi2Te3 stems from its layered hierarchical structure, in which weak van der Waals bonding will probably be the key structural factor in comprehensively improving performance for mass production and wearable application. This prior-knowledge-based FF study is also suggested as a bridge between the theoretical understanding of micro-mechanisms and the experimental measurement of TE material properties, leading to a general framework of molecular simulation for other complex energy materials.},
   author = {Ben Huang and Guodong Li and Xuqiu Yang and Pengcheng Zhai},
   doi = {10.1088/1361-6463/AB2F3A},
   issn = {0022-3727},
   issue = {42},
   journal = {Journal of Physics D: Applied Physics},
   keywords = {Bi2Te3 thermoelectric material,accurate and efficient potential,anharmonicity,anisotropy,mechanical property,thermal property},
   month = {8},
   pages = {425303},
   publisher = {IOP Publishing},
   title = {Capturing anharmonic and anisotropic natures in the thermotics and mechanics of {Bi$_2$Te$_3$} thermoelectric material through an accurate and efficient potential},
   volume = {52},
   url = {https://iopscience.iop.org/article/10.1088/1361-6463/ab2f3a https://iopscience.iop.org/article/10.1088/1361-6463/ab2f3a/meta},
   year = {2019}
}
@article{Huang2017,
   abstract = {In this paper, we applied large-scale molecular dynamics and lattice dynamics to study the influence of mass fluctuation on thermal transport properties in bulk Bi2Te3, namely thermal conductivity (К), phonon density of state (PDOS), group velocity (vg), and mean free path (l). The results show that total atomic mass change can affect the relevant vibrational frequency on the micro level and heat transfer rate in the macro statistic, hence leading to the strength variation of the anharmonic phonon processes (Umklapp scattering) in the defect-free Bi2Te3 bulk. Moreover, it is interesting to find that the anharmonicity of Bi2Te3 can be also influenced by atomic differences of the structure such as the mass distribution in the primitive cell. Considering the asymmetry of the crystal structure and interatomic forces, it can be concluded by phonon frequency, lifetime, and velocity calculation that acoustic-optical phonon scattering shows the structure-sensitivity to the mass distribution and complicates the heat transfer mechanism, hence resulting in the low lattice thermal conductivity of Bi2Te3. This study is helpful for designing the material with tailored thermal conductivity via atomic substitution.},
   author = {Ben Huang and Pengcheng Zhai and Xuqiu Yang and Guodong Li},
   doi = {10.1007/S11664-016-4977-4},
   issn = {03615235},
   issue = {5},
   journal = {Journal of Electronic Materials},
   keywords = {Bi2Te3,Thermal transport,anharmonicity,atomic mass change,lattice dynamics,molecular dynamics},
   month = {5},
   pages = {2797-2806},
   publisher = {Springer New York LLC},
   title = {Effects of Mass Fluctuation on Thermal Transport Properties in Bulk {Bi$_2$Te$_3$}},
   volume = {46},
   year = {2017}
}
@article{Heremans2017,
   abstract = {Tetradymites are M2X3 compounds — in which M is a group V metal, usually Bi or Sb, and X is a group VI anion, Te, Se or S — that crystallize in a rhombohedral structure. Bi2Se3, Bi2Te3 and Sb2Te3 are archetypical tetradymites. Other mixtures of M and X elements produce common variants, such as Bi2Te2Se. Because tetradymites are based on heavy p-block elements, strong spin-orbit coupling greatly influences their electronic properties, both on the surface and in the bulk. Their surface electronic states are a cornerstone of frontier work on topological insulators. The bulk energy bands are characterized by small energy gaps, high group velocities, small effective masses and band inversion near the centre of the Brillouin zone. These properties are favourable for high-efficiency thermoelectric materials but make it difficult to obtain an electrically insulating bulk, which is a requirement of topological insulators. This Review outlines recent progress made in bulk and thin-film tetradymite materials for the optimization of their properties both as thermoelectrics and as topological insulators. Tetradymite-type materials, such as Bi2Te3, have for decades been of interest as excellent thermoelectrics near ambient temperature and have recently enabled many seminal studies on topological insulators. In this Review, we discuss the recent progress in optimizing the properties of bulk and thin-film tetradymites for such studies.},
   author = {Joseph P. Heremans and Robert J. Cava and Nitin Samarth},
   doi = {10.1038/natrevmats.2017.49},
   issn = {2058-8437},
   issue = {10},
   journal = {Nature Reviews Materials 2017 2:10},
   keywords = {Electronic properties and materials,Solid,Thermoelectrics,Topological matter,state chemistry},
   month = {9},
   pages = {1-21},
   publisher = {Nature Publishing Group},
   title = {Tetradymites as thermoelectrics and topological insulators},
   volume = {2},
   url = {https://www.nature.com/articles/natrevmats201749},
   year = {2017}
}
@article{Cardona2001,
   abstract = {During the past ten years, semiconducting crystals with varying isotopic compositions have been grown. They can be used for obtaining detailed information on their lattice dynamics, including dispersion relations, eigenvectors and the self-energies related to anharmonicity and isotopic disorder. Examples involving diamond, zincblende, and wurtzite-type semiconductors are discussed.},
   author = {M. Cardona and T. Ruf},
   doi = {10.1016/S0038-1098(00)00443-9},
   issn = {0038-1098},
   issue = {3},
   journal = {Solid State Communications},
   month = {1},
   pages = {201-212},
   publisher = {Pergamon},
   title = {Phonon self-energies in semiconductors: anharmonic and isotopic contributions},
   volume = {117},
   year = {2001}
}
@article{Tian2017,
   abstract = {The anharmonic effect in thermoelectrics has been a central topic for decades in both condensed matter physics and material science. However, despite the long-believed strong and complex anharmonicity in the Bi2Te3-xSex series, experimental verification of anharmonicity and its evolution with doping remains elusive. We fill this important gap with high-resolution, temperature-dependent Raman spectroscopy in high-quality single crystals of Bi2Te3, Bi2Te2Se, and Bi2Se3 over the temperature range from 4 to 293 K. Klemens's model was employed to explain the renormalization of their phonon linewidths. The phonon energies of Bi2Se3 and Bi2Te3 are analyzed in detail from three aspects: lattice expansion, cubic anharmonicity, and quartic anharmonicity. For the first time, we explain the evolution of anharmonicity in various phonon modes and across the series. In particular, we find that the interplay between cubic and quartic anharmonicity is governed by their distinct dependence on the phonon density of states, providing insights into anomalous anharmonicity designing of new thermoelectrics.},
   author = {Yao Tian and Shuang Jia and R. J. Cava and Ruidan Zhong and John Schneeloch and Genda Gu and Kenneth S. Burch},
   doi = {10.1103/PHYSREVB.95.094104/FIGURES/2/MEDIUM},
   issn = {24699969},
   issue = {9},
   journal = {Physical Review B},
   month = {3},
   pages = {094104},
   publisher = {American Physical Society},
   title = {Understanding the evolution of anomalous anharmonicity in {Bi$_2$Te$_{3-x}$Se$_x$}},
   volume = {95},
   url = {https://journals.aps.org/prb/abstract/10.1103/PhysRevB.95.094104},
   year = {2017}
}
@article{Lowndes1972,
   abstract = {The isobaric temperature dependence of the q = 0 transverse-and longitudinal-optic modes of AgC1, AgBr, TlC1, and TlBr is reported in the range 4-450 K and the isothermal pressure dependence of the transverse-optic modes for pressures up to 10 kbar. These measurements are used to determine the thermal-strain and anharmonic contributions to the self-energy for the q = 0 transverse-optic mode for these materials. The results reveal a near cancellation of the cubic and quartic anharmonic contributions to the self-energy for AgCl and AgBr with the cubic contribution dominating at all temperatures. In the thallium halides the quartic contributions are dominant at all temperatures and are sufficiently large as to dominate the thermal strain contribution to the self-energy, thus causing the mode to be weakly soft.},
   author = {R P Lowndes},
   issue = {4},
   journal = {Phys. Rev. B},
   pages = {1490-1498},
   title = {Anharmonicity in the Silver and Thallium Halides: Far-Infrared Dielectric Response},
   volume = {6},
   year = {1972}
}
@article{Decker2015,
   abstract = {Bismuth telluride filled silicone rubber composite was extruded into millimeter-sized wires using electrospinning. The composite wires were tested in view of the electrical resistance and Seebeck coefficient. The highest electrical resistance measured is 2.9*10 10 ohms. The composite material exhibited high Seebeck effect because silicone rubber exhibits low thermal conductivity as a result of increased phonon scatters. Moreover, compared with the bulk reference material, the thermoelectric property of bismuth telluride is notably enhanced. Due to the inherent flexibility of silicone rubber and thermoelectric property of bismuth telluride, it is possible for making a flexible thermoelectric material for alternative energy applications.},
   author = {Bruce Y Decker and Yong X Gan and Sinclair Calderon},
   issue = {6},
   journal = {Journal of Thermal Engineering},
   keywords = {Thermoelectric materials,bismuth telluride,composite material},
   pages = {402-407},
   title = {Thermoelectric Properties of Bismuth Telluride Filled Silicone},
   volume = {1},
   url = {http://eds.yildiz.edu.tr/},
   year = {2015}
}
@article{Hagmann2017,
   abstract = {You may also like Error regions in quantum state tomography: computational complexity caused by geometry of quantum states Daniel Suess, ukasz Rudnicki, Thiago O maciel et al.-Methods, analysis, and the treatment of systematic errors for the electron electric dipole moment search in thorium monoxide J Baron, W C Campbell, D DeMille et al.-Flexible resources for quantum metrology Nicolai Friis, Davide Orsucci, Michalis Skotiniotis et al.-This content was downloaded from IP address 129.11.69.41 on 01/02/2022 at 18:36 Abstract We demonstrate that the introduction of an elemental beam of Mn during the molecular beam epitaxial growth of Bi 2 Se 3 results in the formation of layers of Bi 2 MnSe 4 that intersperse between layers of pure Bi 2 Se 3. This study revises the assumption held by many who study magnetic topological insulators (TIs) that Mn incorporates randomly at Bi-substitutional sites during epitaxial growth of Mn:Bi 2 Se 3. Here, we report the formation of thin film magnetic TI Bi 2 MnSe 4 with stoichiometric composition that grows in a self-assembled multilayer heterostructure with layers of Bi 2 Se 3 , where the number of Bi 2 Se 3 layers separating the single Bi 2 MnSe 4 layers is approximately defined by the relative arrival rate of Mn ions to Bi and Se ions during growth, and we present its compositional, structural, and electronic properties. We support a model for the epitaxial growth of Bi 2 MnSe 4 in a near-periodic self-assembled layered heterostructure with Bi 2 Se 3 with corresponding theoretical calculations of the energetics of this material and those of similar compositions. Computationally derived electronic structure of these heterostructures demonstrates the existence of topologically nontrivial surface states at sufficient thickness.},
   author = {Joseph A Hagmann and Xiang Li and Sugata Chowdhury and Si-Ning Dong and Sergei Rouvimov and Sujitra J Pookpanratana and Kin Man Yu and Tatyana A Orlova and Trudy B Bolin and Carlo U Segre and David G Seiler and Curt A Richter and Xinyu Liu and Margaret Dobrowolska and Jacek K Furdyna},
   doi = {10.1088/1367-2630/aa759c},
   journal = {New J. Phys},
   keywords = {Bi 2 Se 3,band structure,heterostructure,magnetism,molecular beam epitaxy,quantum matter,topological insulator},
   pages = {85002},
   title = {Molecular beam epitaxy growth and structure of self-assembled {Bi$_2$Se$_3$ }/{Bi$_2$} {MnSe$_4$} multilayer heterostructures},
   volume = {19},
   url = {https://doi.org/10.1088/1367-2630/aa759c},
   year = {2017}
}
@article{Mishra1997,
   abstract = {The electronic structures of the two thermoelectric materials Bi 2 Te 3 and Bi 2 Se 3 are studied using density-functional theory with the spin-orbit interaction included. The electron states in the gap region and the chemical bonding can be described in terms of ppσ interaction between the atomic p orbitals within the 'quintuple' layer. For Bi 2 Se 3 , we find both the valence-band maximum as well as the conduction-band minimum, each with a nearly isotropic effective mass, to occur at the zone centre in agreement with experimental results. For Bi 2 Te 3 , we find that the six valleys for the valence-band maximum are located in the mirror planes of the Brillouin zone and they have a highly anisotropic effective mass, leading to an agreement between the de Haas-van Alphen data for the p-doped samples and the calculated Fermi surface. The calculated conduction band, however, has only two minima, instead of the six minima indicated from earlier experiments. The calculated Seebeck coefficients for both p-type and n-type materials are in agreement with the experiments. Bismuth telluride and its selenide alloys are the classic thermoelectric materials with large Seebeck coefficients and, as such, they have been used in thermoelectric refrigeration for a long time [1, 2]. There have been several attempts to fabricate better thermoelectric materials, and materials such as skutterdite pnictides and superlattices consisting of bismuth-telluride-type layers have been recently proposed [3-7]. In spite of their technological importance and the wealth of existing experimental data on Bi 2 Te 3 and Bi 2 Se 3 , surprisingly enough, serious studies of the electronic structure of these compounds based on theoretical calculations have been started only recently. Several early attempts [8-10] at the theoretical determination of the electronic band structure of Bi 2 Te 3 relied on the empirical pseudopotential approach. To our knowledge, the only density-functional calculation for Bi 2 Te 3 reported in the literature was performed by Thomas et al [11] using the LAPW method. However, in their calculation, even though the spin-orbit coupling effects were recognized to be large and significant, the spin-orbit coupling was included only empirically with a tight-binding fitting procedure, which was not adequate for describing the important details of the valence-and conduction-band valleys of these materials, which are small-band-gap semiconductors. The only band-structure calculation of the other compound, namely Bi 2 Se 3 , reported in the literature is an early calculation using a pseudopotential technique [12]. In this paper, we study the electronic band structures of Bi 2 Te 3 and Bi 2 Se 3 on the basis of density-functional calculations taking spin-orbit coupling effects into account. The crystal structures of both Bi 2 Se 3 and Bi 2 Te 3 are rhombohedral with the space group D 5 3d (R ¯ 3m) [13, 14] with five atoms in the trigonal unit cell. The structure is most simply},
   author = {S K Mishra and S Satpathy and O Jepsen},
   journal = {J. Phys.: Condens. Matter},
   pages = {461-470},
   title = {Electronic structure and thermoelectric properties of bismuth telluride and bismuth selenide},
   volume = {9},
   year = {1997}
}
@article{Lee2014,
   abstract = {Understanding the lattice dynamics and low thermal conductivities of IV–VI, V2–VI3 and V materials is critical to the development of better thermoelectric and phase-change materials. Here we provide a link between chemical bonding and low thermal conductivity. Our first-principles calculations reveal that long-ranged interaction along the 〈100〉 direction of the rocksalt structure exist in lead chalcogenides, SnTe, Bi2Te3, Bi and Sb due to the resonant bonding that is common to all of them. This long-ranged interaction in lead chalcogenides and SnTe cause optical phonon softening, strong anharmonic scattering and large phase space for three-phonon scattering processes, which explain why rocksalt IV–VI compounds have much lower thermal conductivities than zincblende III–V compounds. The new insights on the relationship between resonant bonding and low thermal conductivity will help in the development of better thermoelectric and phase change materials. Understanding the link between thermal conductivity and chemical bonding is important for the development of thermoelectric and phase-change materials. Here, the authors associate the low thermal conductivity of IV–VI materials with near-ferroelectric behaviour from their resonant bonding.},
   author = {Sangyeop Lee and Keivan Esfarjani and Tengfei Luo and Jiawei Zhou and Zhiting Tian and Gang Chen},
   doi = {10.1038/ncomms4525},
   issn = {2041-1723},
   issue = {1},
   journal = {Nature Communications 2014 5:1},
   keywords = {Theory and computation,Thermoelectrics},
   month = {4},
   pages = {1-8},
   publisher = {Nature Publishing Group},
   title = {Resonant bonding leads to low lattice thermal conductivity},
   volume = {5},
   url = {https://www.nature.com/articles/ncomms4525},
   year = {2014}
}
@article{Deshko2016,
   abstract = {We investigate the propagation of surface plasmon polaritons (SPPs) in thin films of topological insulators. Cases of single films and multilayered stacks are analyzed. The materials considered are second generation three dimensional topological insulators Bi2Se3, Bi2Te3, and Sb2Te3. Dispersion relations and propagation lengths of SPPs are estimated numerically, taking into account the variation of bulk dielectric functions of topological insulators, as well as substrate, using the Drude-Lorentz model. The key factors affecting propagation length are identified and experimental modifications for tuning the dispersion relations are proposed. The apparent discrepancy between the experimental data and previously considered theory is resolved.},
   author = {Yury Deshko and Lia Krusin-Elbaum and Vinod Menon and Alexander Khanikaev and Jacob Trevino},
   doi = {10.1364/OE.24.007398},
   issn = {1094-4087},
   issue = {7},
   journal = {Optics Express, Vol. 24, Issue 7, pp. 7398-7410},
   keywords = {Optical materials,Optical superlattices,Quantum cascade semiconductor lasers,Quantum computing,Surface plasmon polaritons,Thin films},
   month = {4},
   pages = {7398-7410},
   publisher = {Optical Society of America},
   title = {Surface plasmon polaritons in topological insulator nano-films and superlattices},
   volume = {24},
   url = {https://opg.optica.org/viewmedia.cfm?uri=oe-24-7-7398&seq=0&html=true https://opg.optica.org/abstract.cfm?uri=oe-24-7-7398 https://opg.optica.org/oe/abstract.cfm?uri=oe-24-7-7398},
   year = {2016}
}
@article{Skelton2016,
   abstract = {The layered semiconductor SnSe is one of the highest-performing thermoelectric materials known. We demonstrate, through a first-principles lattice-dynamics study, that the high-temperature Cmcm phase is a dynamic average over lower-symmetry minima separated by very small energetic barriers. Compared to the low-temperature Pnma phase, the Cmcm phase displays a phonon softening and enhanced three-phonon scattering, leading to an anharmonic damping of the low-frequency modes and hence the thermal transport. We develop a renormalization scheme to quantify the effect of the soft modes on the calculated properties, and confirm that the anharmonicity is an inherent feature of the Cmcm phase. These results suggest a design concept for thermal insulators and thermoelectric materials, based on displacive instabilities, and highlight the power of lattice-dynamics calculations for materials characterization.},
   author = {Jonathan M. Skelton and Lee A. Burton and Stephen C. Parker and Aron Walsh and Chang Eun Kim and Aloysius Soon and John Buckeridge and Alexey A. Sokol and C. Richard A. Catlow and Atsushi Togo and Isao Tanaka},
   doi = {10.1103/PHYSREVLETT.117.075502/FIGURES/3/MEDIUM},
   issn = {10797114},
   issue = {7},
   journal = {Physical Review Letters},
   month = {8},
   pages = {075502},
   publisher = {American Physical Society},
   title = {Anharmonicity in the High-Temperature {Cmcm} Phase of {SnSe}: Soft Modes and Three-Phonon Interactions},
   volume = {117},
   url = {https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.117.075502},
   year = {2016}
}
@article{Bacon2016,
   abstract = {We report on large-area photoconductive terahertz (THz) emitters with a low-temperature-grown GaAs (LT-GaAs) active layer fabricated on quartz substrates using a lift-off transfer process. These devices are compared to the same LT-GaAs emitters when fabricated on the growth substrate. We find that the transferred devices show higher optical-to-THz conversion efficiencies and significantly larger breakdown fields, which we attribute to reduced parasitic current in the substrate. Through these improvements, we demonstrate a factor of ∼8 increase in emitted THz field strength at the maximum operating voltage. In addition we find improved performance when these devices are used for photoconductive detection, which we explain through a combination of reduced parasitic substrate currents and reduced space-charge build-up in the device.},
   author = {David R Bacon and Andrew D Burnett and Matthew Swithenbank and Christopher Russell and Lianhe Li and Christopher D Wood and John Cunningham and Edmund H Linfield and A Giles Davies and Paul Dean and Joshua R Freeman},
   doi = {10.1364/OE.24.026986},
   issue = {23},
   journal = {Optics Express},
   pages = {26986-26997},
   title = {Free-space terahertz radiation from a {LT-GaAs}-on-quartz large-area photoconductive emitter},
   volume = {24},
   url = {http://dx.doi.org/10.1364/OE.24.026986},
   year = {2016}
}
@article{Monkhorst1976,
   author = {Hendrik J Monkhorst and James D Pack},
   doi = {10.1103/PhysRevB.13.5188},
   issue = {12},
   journal = {Phys. Rev. B},
   month = {6},
   pages = {5188-5192},
   publisher = {American Physical Society},
   title = {Special points for Brillouin-zone integrations},
   volume = {13},
   url = {https://link.aps.org/doi/10.1103/PhysRevB.13.5188},
   year = {1976}
}
@article{Jain2013,
   author = {Anubhav Jain and Shyue Ping Ong and Geoffroy Hautier and Wei Chen and William Davidson Richards and Stephen Dacek and Shreyas Cholia and Dan Gunter and David Skinner and Gerbrand Ceder and Kristin a. Persson},
   doi = {10.1063/1.4812323},
   issn = {2166532X},
   issue = {1},
   journal = {APL Materials},
   pages = {11002},
   title = {The Materials Project: A materials genome approach to accelerating materials innovation},
   volume = {1},
   url = {http://link.aip.org/link/AMPADS/v1/i1/p011002/s1&Agg=doi},
   year = {2013}
}
@article{Blochl1994,
   author = {Peter E Blöchl},
   issue = {24},
   journal = {Physical Review B},
   pages = {17953},
   publisher = {APS},
   title = {Projector augmented-wave method},
   volume = {50},
   year = {1994}
}
@article{phonopy,
   author = {A Togo and I Tanaka},
   journal = {Scr. Mater.},
   month = {11},
   pages = {1-5},
   title = {First principles phonon calculations in materials science},
   volume = {108},
   year = {2015}
}
@article{Hafner2008,
   author = {Jürgen Hafner},
   doi = {10.1002/jcc.21057},
   isbn = {1096-987X},
   issn = {01928651},
   issue = {13},
   journal = {Journal of Computational Chemistry},
   keywords = {Catalysis,Density-functional theory,Hybrid functionals,Many-body perturbation theory,Materials science,Plane-wave basis,Projector-augmented-waves,Pseudopotentials,Solid state chemistry,Solid state physics,Surface science},
   month = {10},
   pages = {2044-2078},
   pmid = {20928852},
   title = {Ab-initio simulations of materials using {VASP}: Density-functional theory and beyond},
   volume = {29},
   year = {2008}
}
@article{Perdew1996,
   author = {John P Perdew and Kieron Burke and Matthias Ernzerhof},
   doi = {10.1103/PhysRevLett.77.3865},
   issn = {0031-9007},
   issue = {18},
   journal = {Physical Review Letters},
   month = {10},
   pages = {3865-3868},
   title = {Generalized Gradient Approximation Made Simple},
   volume = {77},
   year = {1996}
}
@article{Grimme2011,
   author = {Stefan Grimme and Stephan Ehrlich and Lars Goerigk},
   doi = {10.1002/jcc.21759},
   issn = {01928651},
   issue = {7},
   journal = {Journal of Computational Chemistry},
   keywords = {density functional theory,dispersion energy,noncovalent interactions,van der waals complexes},
   month = {5},
   pages = {1456-1465},
   title = {Effect of the damping function in dispersion corrected density functional theory},
   volume = {32},
   url = {http://doi.wiley.com/10.1002/jcc.21759},
   year = {2011}
}
@article{Becke2005,
   author = {Axel D Becke and Erin R Johnson},
   doi = {10.1063/1.2065267},
   issn = {0021-9606},
   issue = {15},
   journal = {The Journal of Chemical Physics},
   month = {10},
   pages = {154101},
   title = {A density-functional model of the dispersion interaction},
   volume = {123},
   url = {http://aip.scitation.org/doi/10.1063/1.2065267},
   year = {2005}
}
@article{Huggard2000,
   abstract = {Time domain spectroscopy has been used to measure the room temperature transmission of highly doped GaAs in the frequency range from 0.2 to above 3 THz. We studied n- and p-type layers, with carrie...},
   author = {P. G. Huggard and J. A. Cluff and G. P. Moore and C. J. Shaw and S. R. Andrews and S. R. Keiding and E. H. Linfield and D. A. Ritchie},
   doi = {10.1063/1.372238},
   issn = {0021-8979},
   issue = {5},
   journal = {Journal of Applied Physics},
   keywords = {Hall mobility,III-V semiconductors,absorption coefficients,carrier density,gallium arsenide,high-frequency effects,infrared spectra,time resolved spectra},
   month = {2},
   pages = {2382},
   publisher = {American Institute of PhysicsAIP},
   title = {Drude conductivity of highly doped {GaAs} at terahertz frequencies},
   volume = {87},
   url = {https://aip.scitation.org/doi/abs/10.1063/1.372238},
   year = {2000}
}
@article{Nashima2001,
   abstract = {Complex conductivity of moderately P-doped silicon wafers (1.1±0.2 Ω cm at room temperature) has been measured by using a terahertz (THz) time-domain spectroscopy for the temperature and frequency ...},
   author = {S. Nashima and O. Morikawa and K. Takata and M. Hangyo},
   doi = {10.1063/1.1376673},
   issn = {0021-8979},
   issue = {2},
   journal = {Journal of Applied Physics},
   keywords = {carrier mobility,electrical conductivity,elemental semiconductors,phosphorus,silicon,submillimetre wave spectra},
   month = {6},
   pages = {837},
   publisher = {American Institute of PhysicsAIP},
   title = {Temperature dependence of optical and electronic properties of moderately doped silicon at terahertz frequencies},
   volume = {90},
   url = {https://aip.scitation.org/doi/abs/10.1063/1.1376673},
   year = {2001}
}
@article{Kabir2006,
   abstract = {Frequency-dependent complex conductivity of high-mobility GaAs and InAs two-dimensional-electron-gas (2DEG) systems is studied by terahertz time domain spectroscopy. Determining the momentum relaxa...},
   author = {N. A. Kabir and Y. Yoon and J. R. Knab and J. Y. Chen and A. G. Markelz and J. L. Reno and Y. Sadofyev and S. Johnson and Y. H. Zhang and J. P. Bird},
   doi = {10.1063/1.2357605},
   issn = {0003-6951},
   issue = {13},
   journal = {Applied Physics Letters},
   keywords = {III-V semiconductors,carrier mobility,electrical conductivity,gallium arsenide,heating,indium compounds,submillimetre wave spectra,two-dimensional electron gas},
   month = {9},
   pages = {132109},
   publisher = {American Institute of PhysicsAIP},
   title = {Terahertz transmission characteristics of high-mobility {GaAs} and {InAs} two-dimensional-electron-gas systems},
   volume = {89},
   url = {https://aip.scitation.org/doi/abs/10.1063/1.2357605},
   year = {2006}
}
@article{Wang2017,
   abstract = {In this article, the authors report on the growth of the topological insulator alloy Bi2(Se1−xTex)3 by molecular beam epitaxy. A variety of flux ratios and substrate temperatures are used to contro...},
   author = {Yong Wang and Theresa P. Ginley and Chiyu Zhang and Stephanie Law},
   doi = {10.1116/1.4976622},
   issn = {2166-2746},
   issue = {2},
   journal = {Journal of Vacuum Science and Technology B, Nanotechnology and Microelectronics: Materials, Processing, Measurement, and Phenomena},
   keywords = {Hall mobility,bismuth compounds,carrier density,molecular beam epitaxial growth,semiconductor epitaxial layers,semiconductor growth,topological insulators},
   month = {2},
   pages = {02B106},
   publisher = {American Vacuum SocietyAVS},
   title = {Transport properties of {Bi$_2$(Se$_{1−x}$Te$_x$)$_3$} thin films grown by molecular beam epitaxy},
   volume = {35},
   url = {https://avs.scitation.org/doi/abs/10.1116/1.4976622},
   year = {2017}
}
@article{Bathon2016,
   abstract = {A Bi2Te3 single crystal is grown with the modified Bridgman technique. The crystal has a nominal composition with a Te content of 61 mol% resulting in the existence of two distinct regions, p- and n-doped, respectively; color-coded tunneling spectra are taken over 60 nm at the transition region.},
   author = {Thomas Bathon and Simona Achilli and Paolo Sessi and Vladimir Andreevich Golyashov and Konstantin Aleksandrovich Kokh and Oleg Evgenievich Tereshchenko and Matthias Bode},
   doi = {10.1002/ADMA.201504771},
   issn = {15214095},
   issue = {11},
   journal = {Advanced Materials},
   keywords = {density functional theory,p-n junctions,scanning tunneling microscopy,topological insulators,transport},
   month = {3},
   pages = {2183-2188},
   publisher = {Wiley-VCH Verlag},
   title = {Experimental Realization of a Topological p-n Junction by Intrinsic Defect Grading},
   volume = {28},
   year = {2016}
}
@article{Wang2011,
   abstract = {Topological insulator thin films of Bi2Te3 with controlled electronic structure can be grown by regulating the molecular beam epitaxy (MBE) growth kinetics without any extrinsic doping. N- to p-type conversion results from the change in the concentrations of TeBi donors and BiTe acceptors. This represents a step toward controlling topological surface states, with potential applications in devices. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.},
   author = {Guang Wang and Xie Gang Zhu and Yi Yang Sun and Yao Yi Li and Tong Zhang and Jing Wen and Xi Chen and Ke He and Li Li Wang and Xu Cun Ma and Jin Feng Jia and Shengbai B. Zhang and Qi Kun Xue},
   doi = {10.1002/ADMA.201100678},
   issn = {09359648},
   issue = {26},
   journal = {Advanced Materials},
   keywords = {angle-resolved photoemission spectroscopy,electronic structures,first-principles calculations,scanning tunneling microscopy,topological insulators},
   month = {7},
   pages = {2929-2932},
   pmid = {21544877},
   title = {Topological insulator thin films of {Bi$_2$Te$_3$} with controlled electronic structure},
   volume = {23},
   year = {2011}
}
@article{Allen1974,
   abstract = {Effects of the dynamical properties of phonons on the electronic properties of metals are treated through the use of the phonon spectral weight function. It is shown that the leading behavior of the electron quasiparticle lifetime is lowered to quadratic in the frequency or temperature from the cubic behavior which is well known to occur for infinitely sharp phonons. Explicit evaluations of 1τ are made using an extension of the Debye model which allows for a finite phonon lifetime. The mass-enhancement parameter λ is discussed and is shown formally to be related to the static phonon propagator. Thus if there is a difference between the phonon relaxation at zero frequency and at the phonon frequency, it is possible for the phonon frequencies which determine λ to differ significantly from the peak frequencies observed in inelastic neutron scattering. The implications of these results for superconducting transition temperatures are discussed with particular reference to recent neutron scattering experiments in Nb3Sn. © 1974 The American Physical Society.},
   author = {Philip B. Allen and Richard Silberglitt},
   doi = {10.1103/PhysRevB.9.4733},
   issn = {01631829},
   issue = {11},
   journal = {Physical Review B},
   month = {6},
   pages = {4733},
   publisher = {American Physical Society},
   title = {Some effects of phonon dynamics on electron lifetime, mass renormalization, and superconducting transition temperature},
   volume = {9},
   url = {https://journals.aps.org/prb/abstract/10.1103/PhysRevB.9.4733},
   year = {1974}
}
@article{Zhang2008,
   abstract = {Electron-phonon renormalization and phonon anharmonicity in metals are investigated by employing density functional theory based first-principles electronic structure methods. Using doped silicon, diamond, and MgB2 as examples, it is shown that phonon anharmonicity may be significantly renormalized by electron-phonon interactions, especially for phonon modes that couple strongly with electrons. The unusually large third-order anharmonic potential of the E2 g phonon in MgB2 is largely due to the electron-phonon renormalization effect. © 2008 Elsevier Ltd. All rights reserved.},
   author = {Peihong Zhang and Yu Xue and Pratibha Dev},
   doi = {10.1016/J.SSC.2008.07.034},
   issn = {0038-1098},
   issue = {3-4},
   journal = {Solid State Communications},
   keywords = {D. Anharmonicity,D. Electron-phonon},
   month = {10},
   pages = {151-154},
   publisher = {Pergamon},
   title = {Electron–phonon renormalization and phonon anharmonicity in metals},
   volume = {148},
   year = {2008}
}
@article{Ponosov2016,
   abstract = {We report a Raman study of the effect of temperature on the self-energies of optical phonons in a number of transition metals with hexagonal-close-packed structure. Anisotropic softening of phonon energies and narrowing of phonon linewidths with increasing temperature are observed. These effects are reproduced in the calculations of phonon spectral functions based on ab initio electronic structures and with carrier scattering by phonons taken into account. The combined observations and results of simulations indicate a relation between observed anomalies and the renormalization of the electron spectrum due to electron-phonon interaction. It is emphasized that the temperature dependence of the phonon energies resembles anharmonic behavior but is actually an electron-induced effect.},
   author = {Yu S. Ponosov and S. V. Streltsov},
   doi = {10.1103/PHYSREVB.94.214302/FIGURES/8/MEDIUM},
   issn = {24699969},
   issue = {21},
   journal = {Physical Review B},
   month = {12},
   pages = {214302},
   publisher = {American Physical Society},
   title = {Raman evidence for nonadiabatic effects in optical phonon self-energies of transition metals},
   volume = {94},
   url = {https://journals.aps.org/prb/abstract/10.1103/PhysRevB.94.214302},
   year = {2016}
}
@article{Maksimov1996,
   abstract = {The nonadiabatic renormalization of optical phonon frequencies and linewidths is studied. The phonon self-energy is calculated in the one-loop approximation including electron-phonon interaction and impurity scattering. The wave vector dispersion and the temperature dependence of the phonon self-energy are calculated for two model Eliashberg spectral functions. It is shown that a strong electron-phonon interaction diminishes the nonadiabatic renormalization of a phonon frequency and shifts the maximum of the linewidth to the values of qvF higher than it follows for Landau damping of noninteracting electrons. The vertex corrections are studied for a system with isotropic impurity scattering. It is shown that they can give in some cases a serious qualitative contribution to the nonadiabatic renormalzation of phonon frequencies and linewidths.},
   author = {E. G. Maksimov and S. V. Shulga},
   doi = {10.1016/0038-1098(95)00745-8},
   issn = {0038-1098},
   issue = {7},
   journal = {Solid State Communications},
   month = {2},
   pages = {553-560},
   publisher = {Pergamon},
   title = {Nonadiabatic effects in optical phonon self-energy},
   volume = {97},
   year = {1996}
}
@article{Goodrich2004,
   abstract = {We compared methods of measuring the residual resistivity ratio (RRR) of high‐purity Nb using transport current. Our experimental study is intended to answer some fundamental questions about the be...},
   author = {L. F. Goodrich and T. C. Stauffer and J. D. Splett and D. F. Vecchia},
   doi = {10.1063/1.1774550},
   isbn = {073540187X},
   issn = {0094-243X},
   issue = {1},
   journal = {AIP Conference Proceedings},
   keywords = {cryogenics,electrical resistivity,magnetic field effects,magnetoresistance,niobium,numerical analysis},
   month = {7},
   pages = {41},
   publisher = {American Institute of PhysicsAIP},
   title = {Measuring Residual Resistivity Ratio of High‐Purity Nb},
   volume = {711},
   url = {https://aip.scitation.org/doi/abs/10.1063/1.1774550},
   year = {2004}
}
@article{Zhao2020,
   abstract = {We use ab initio self-consistent phonon theory combined with compressive sensing techniques to investigate the role of quartic anharmonicity in the lattice dynamics and thermal transport properties of the cubic antiperovskites A3BO (A=K, Rb; B=Br, Au). Our findings indicate that the strong quartic anharmonicity of alkali-metal atoms plays a crucial role in the phonon quasiparticles free from imaginary frequencies in K3BrO, Rb3BrO, and Rb3AuO, and gives rise to an evident hardening of vibrational frequencies of the low-lying modes in K3AuO. Based on these results, the lattice thermal transport properties are predicted through the Boltzmann transport equation within the relaxation time approximation. The results exhibit that the four cubic antiperovskites have remarkably low thermal conductivities κL, e.g., 0.73-1.70 W/mK at 300 K, and an anomalously weak temperature dependence of the κL, e.g., κL∼T-0.3, of which the latter has not been reported in normal perovskites and other conventional semiconductors to date. We demonstrate that the strong three-phonon scattering along with strong quartic anharmonic renormalization of the soft modes and the presence of high-frequency dispersive optical modes are responsible for the thermal conductivity spectrum κL(ω) and thus the low κL and its anomalously weak temperature dependence.},
   author = {Yinchang Zhao and Chao Lian and Shuming Zeng and Zhenhong Dai and Sheng Meng and Jun Ni},
   doi = {10.1103/PHYSREVB.101.184303/FIGURES/4/MEDIUM},
   issn = {24699969},
   issue = {18},
   journal = {Physical Review B},
   month = {5},
   pages = {184303},
   publisher = {American Physical Society},
   title = {Quartic anharmonicity and anomalous thermal conductivity in cubic antiperovskites A3B O (A= K, Rb; B=Br, Au) Quartic Anharmonicity and Anomalous Thermal ... Zhao, Lian, Zeng, Dai, Meng, and Ni},
   volume = {101},
   url = {https://journals.aps.org/prb/abstract/10.1103/PhysRevB.101.184303},
   year = {2020}
}
@article{Xia2018,
   abstract = {We perform a first-principles study of lattice thermal transport in PbTe by explicitly considering anharmonicity up to 4th order. To determine the temperature-dependent lattice constant of PbTe bey...},
   author = {Yi Xia},
   doi = {10.1063/1.5040887},
   issn = {0003-6951},
   issue = {7},
   journal = {Applied Physics Letters},
   keywords = {IV-VI semiconductors,ab initio calculations,lattice constants,lead compounds,phonon-phonon interactions,renormalisation,thermal conductivity,thermal expansion,vibrational modes},
   month = {8},
   pages = {073901},
   publisher = {AIP Publishing LLCAIP Publishing},
   title = {Revisiting lattice thermal transport in PbTe: The crucial role of quartic anharmonicity},
   volume = {113},
   url = {https://aip.scitation.org/doi/abs/10.1063/1.5040887},
   year = {2018}
}
@article{Tian2011,
   abstract = {The contribution of optical phonons to thermal conductivity has typically been ignored. However, when the system size decreases to the nanoscale regime, optical phonons are no longer negligible. In...},
   author = {Zhiting Tian and Keivan Esfarjani and Junichiro Shiomi and Asegun S. Henry and Gang Chen},
   doi = {10.1063/1.3615709},
   issn = {0003-6951},
   issue = {5},
   journal = {Applied Physics Letters},
   keywords = {ab initio calculations,carrier mean free path,elemental semiconductors,nanowires,phonons,semiconductor quantum wires,silicon,thermal conductivity},
   month = {8},
   pages = {053122},
   publisher = {American Institute of PhysicsAIP},
   title = {On the importance of optical phonons to thermal conductivity in nanostructures},
   volume = {99},
   url = {https://aip.scitation.org/doi/abs/10.1063/1.3615709},
   year = {2011}
}
@article{Knox2022,
   author = {Craig S. Knox and Matthew T. Vaughan and Andrew D. Burnett and Mannan Ali and Satoshi Sasaki and Edmund H. Linfield and Alexander Giles Davies and Joshua R. Freeman},
   doi = {10.1103/PhysRevB.106.245203},
   issn = {2469-9950},
   issue = {24},
   journal = {Physical Review B},
   month = {12},
   pages = {245203},
   publisher = {American Physical Society},
   title = {Effects of structural ordering on infrared active vibrations within    {Bi$_ 2$    (  Te $_{ ( 1 − x )}$    Se$_x$  )$_ 3$}},
   volume = {106},
   url = {https://link.aps.org/doi/10.1103/PhysRevB.106.245203},
   year = {2022}
}
@article{Zhang2005,
   abstract = {When electrons are confined in two-dimensional materials, quantum-mechanically enhanced transport phenomena such as the quantum Hall effect can be observed. Graphene, consisting of an isolated single atomic layer of graphite, is an ideal realization of such a two-dimensional system. However, its behaviour is expected to differ markedly from the well-studied case of quantum wells in conventional semiconductor interfaces. This difference arises from the unique electronic properties of graphene, which exhibits electron–hole degeneracy and vanishing carrier mass near the point of charge neutrality1,2. Indeed, a distinctive half-integer quantum Hall effect has been predicted3,4,5 theoretically, as has the existence of a non-zero Berry's phase (a geometric quantum phase) of the electron wavefunction—a consequence of the exceptional topology of the graphene band structure6,7. Recent advances in micromechanical extraction and fabrication techniques for graphite structures8,9,10,11,12 now permit such exotic two-dimensional electron systems to be probed experimentally. Here we report an experimental investigation of magneto-transport in a high-mobility single layer of graphene. Adjusting the chemical potential with the use of the electric field effect, we observe an unusual half-integer quantum Hall effect for both electron and hole carriers in graphene. The relevance of Berry's phase to these experiments is confirmed by magneto-oscillations. In addition to their purely scientific interest, these unusual quantum transport phenomena may lead to new applications in carbon-based electronic and magneto-electronic devices.},
   author = {Yuanbo Zhang and Yan Wen Tan and Horst L. Stormer and Philip Kim},
   doi = {10.1038/nature04235},
   issn = {1476-4687},
   issue = {7065},
   journal = {Nature 2005 438:7065},
   keywords = {Humanities and Social Sciences,Science,multidisciplinary},
   month = {11},
   pages = {201-204},
   pmid = {16281031},
   publisher = {Nature Publishing Group},
   title = {Experimental observation of the quantum Hall effect and Berry's phase in graphene},
   volume = {438},
   url = {https://www.nature.com/articles/nature04235},
   year = {2005}
}
@article{Ren2010,
   abstract = {Topological insulators are predicted to present interesting surface transport phenomena but their experimental studies have been hindered by a metallic bulk conduction that overwhelms the surface transport. We show that the topological insulator Bi2 Te2 Se presents a high resistivity exceeding 1Ωcm and a variable-range hopping behavior, and yet presents Shubnikov-de Haas oscillations coming from the topological surface state. Furthermore, we have been able to clarify both the bulk and surface transport channels, establishing a comprehensive understanding of the transport in this material. Our results demonstrate that Bi2 Te2 Se is, to our knowledge, the best material to date for studying the surface quantum transport in a topological insulator. © 2010 The American Physical Society.},
   author = {Zhi Ren and A. A. Taskin and Satoshi Sasaki and Kouji Segawa and Yoichi Ando},
   doi = {10.1103/PHYSREVB.82.241306/FIGURES/3/MEDIUM},
   issn = {10980121},
   issue = {24},
   journal = {Physical Review B - Condensed Matter and Materials Physics},
   month = {12},
   pages = {241306},
   publisher = {American Physical Society},
   title = {Large bulk resistivity and surface quantum oscillations in the topological insulator {Bi$_2$ Te$_2$ Se}},
   volume = {82},
   url = {https://journals.aps.org/prb/abstract/10.1103/PhysRevB.82.241306},
   year = {2010}
}
@article{Steinberg2011,
   abstract = {We study coherent electronic transport in charge-density-tunable microdevices patterned from thin films of the topological insulator (TI) Bi 2Se 3. The devices exhibit pronounced electric field effect, including ambipolar modulation of the resistance with an on-and-off ratio of 500%. We show that the weak antilocalization correction to conductance is sensitive to the number of coherently coupled channels, which in a TI includes the top and bottom surfaces and the bulk carriers. These are separated into coherently independent channels by the application of gate voltage and at elevated temperatures. Our results are consistent with a model where channel separation is determined by a competition between the phase coherence time and the surface-to-bulk scattering time. © 2011 American Physical Society.},
   author = {H. Steinberg and J. B. Laloë and V. Fatemi and J. S. Moodera and P. Jarillo-Herrero},
   doi = {10.1103/PHYSREVB.84.233101/FIGURES/4/MEDIUM},
   issn = {10980121},
   issue = {23},
   journal = {Physical Review B - Condensed Matter and Materials Physics},
   month = {12},
   pages = {233101},
   publisher = {American Physical Society},
   title = {Electrically tunable surface-to-bulk coherent coupling in topological insulator thin films},
   volume = {84},
   url = {https://journals.aps.org/prb/abstract/10.1103/PhysRevB.84.233101},
   year = {2011}
}
@article{Taskin2011,
   abstract = {A distinguishing feature of Dirac fermions is the Berry phase of π associated with their cyclotron motions. Since this Berry phase can be experimentally assessed by analyzing the Landau-level fan diagram of the Shubnikov-de Haas (SdH) oscillations, such an analysis has been widely employed in recent transport studies of topological insulators to elucidate the Dirac nature of the surface states. However, the reported results have usually been unconvincing. Here we show a general scheme for describing the phase factor of the SdH oscillations in realistic surface states of topological insulators, and demonstrate how one can elucidate the Dirac nature in real experimental data. © 2011 American Physical Society.},
   author = {A. A. Taskin and Yoichi Ando},
   doi = {10.1103/PHYSREVB.84.035301},
   issn = {10980121},
   issue = {3},
   journal = {Physical Review B - Condensed Matter and Materials Physics},
   month = {7},
   pages = {035301},
   publisher = {American Physical Society},
   title = {Berry phase of nonideal Dirac fermions in topological insulators},
   volume = {84},
   url = {https://journals.aps.org/prb/abstract/10.1103/PhysRevB.84.035301},
   year = {2011}
}
@article{Jauregui2015,
   abstract = {Transport due to spin-helical massless Dirac fermion surface state is of paramount importance to realize various new physical phenomena in topological insulators, ranging from quantum anomalous Hall effect to Majorana fermions. However, one of the most important hallmarks of topological surface states, the Dirac linear band dispersion, has been difficult to reveal directly in transport measurements. Here we report experiments on Bi 2 Te 3 nanoribbon ambipolar field effect devices on high-k SrTiO 3 substrates, where we achieve a gate-tuned bulk metal-insulator transition and the topological transport regime with substantial surface state conduction. In this regime, we report two unambiguous transport evidences for gate-tunable Dirac fermions through p Berry's phase in Shubnikov-de Haas oscillations and effective mass proportional to the Fermi momentum, indicating linear energy-momentum dispersion. We also measure a gate-tunable weak anti-localization (WAL) with 2 coherent conduction channels (indicating 2 decoupled surfaces) near the charge neutrality point, and a transition to weak localization (indicating a collapse of the Berry's phase) when the Fermi energy approaches the bulk conduction band. The gate-tunable Dirac fermion topological surface states pave the way towards a variety of topological electronic devices. T he extraordinary electronic properties of topological insulators 1-3 (TIs) make them a unique class of materials relevant for applications such as low power electronic devices, spintronics 1 and fault-tolerant quantum computation 4,5. TIs feature topologically non-trivial surface states, where carriers are massless relativistic particles with linear energy-momentum band dispersion and with spins locked perpendicular to their momentum 2,3. Existence of such helical Dirac fermion surface states have been experimentally confirmed by angle-resolved photoemission spectroscopy (ARPES) 6,7 and scanning-tunneling microscopy 8. Transport measurements in bulk crystals of TI (such as Bi 2 Te 3) 9 have met more challenges to probe the surface states, because of the non-insulating bulk conduction. In order to reduce the bulk contribution and enhance the surface contribution in TI transport, a number of efforts have been made by growing bulk single-crystals with fine-tuned composition 10-13 , adding compensating dopants 14,15 , growing ultrathin films and nanostructures such as nano-wires 16,17 or nanoribbons (NRs) 11,18 , and using electrical gating 19-21 to tune the Fermi energy (E F). Nanostructures, with a high surface-to-volume ratio, have been shown to enhance the surface conduction contribution. However, in previous reports, unambiguous measurements of the topological surface states (e.g p-Berry's phase and Dirac fermion dispersion) remain challenging. In this work, we combine nanostructures with ultrahigh-k gate dielectric by placing Bi 2 Te 3 NRs on SrTiO 3 (STO) substrates 22,23. We realize the topological transport regime where bulk is insulating and surface substantially contributes to the conduction, and report clear evidence of the Dirac fermion nature of the gate-tunable topological surface states, directly revealing the characteristic linear energy-momentum dispersion via density-dependent effective mass measurements. The excellent gate tunability of E F (from surface states to bulk conduction band) has also enabled us to observe a predicted transition from the usual weak anti-localization (WAL) behavior to weak localization (WL), reflecting a change in the pseudospin texture and Berry's phase of the quantum coherent charge carriers 24,25. The Bi 2 Te 3 NRs were synthesized by catalyst-free vapor solid method, following an approach similar to that of Kong et al. 26 for thin films. NRs are grown out of the plane of the substrate and they are individually transferred to other substrates or support for further studies, using an electrochemically sharpened tungsten probe and an optical microscope. We have used transmission electron microscopy (TEM) to determine the structural OPEN},
   author = {Luis A Jauregui and Michael T Pettes and Leonid P Rokhinson and Li Shi and Yong P Chen},
   doi = {10.1038/srep08452},
   title = {Gate Tunable Relativistic Mass and Berry's phase in Topological Insulator Nanoribbon Field Effect Devices},
   url = {www.nature.com/scientificreports},
   year = {2015}
}
@article{Chen2011-2,
   abstract = {We demonstrate that the weak antilocalization effect can serve as a convenient method for detecting decoupled surface transport in topological insulator thin films. In the regime where a bulk Fermi surface coexists with the surface states, the low-field magnetoconductivity is well described by the Hikami-Larkin-Nagaoka equation for single-component transport of noninteracting electrons. When the electron density is lowered, the magnetotransport behavior deviates from the single-component description and strong evidence is found for independent conducting channels at or near the bottom and top surfaces. The magnetic-field-dependent part of corrections to conductivity due to Zeeman energy is shown to be negligible for the fields relevant to the weak antilocalization despite considerable electron-electron interaction effects on the temperature dependence of the conductivity. © 2011 American Physical Society.},
   author = {J. Chen and X. Y. He and K. H. Wu and Z. Q. Ji and L. Lu and J. R. Shi and J. H. Smet and Y. Q. Li},
   doi = {10.1103/PHYSREVB.83.241304/FIGURES/3/MEDIUM},
   issn = {10980121},
   issue = {24},
   journal = {Physical Review B - Condensed Matter and Materials Physics},
   month = {6},
   pages = {241304},
   publisher = {American Physical Society},
   title = {Tunable surface conductivity in {Bi$_2$ Se$_3$} revealed in diffusive electron transport},
   volume = {83},
   url = {https://journals.aps.org/prb/abstract/10.1103/PhysRevB.83.241304},
   year = {2011}
}
@article{Yang2015,
   abstract = {Observations of novel quantum phenomena expected for three-dimensional topological insulators (TIs) often require fabrications of thin-film devices and tuning of the Fermi level across the Dirac point. Since thin films have both top and bottom surfaces, an effective control of the surface chemical potential requires dual gating. However, a reliable dual-gating technique for TI thin films has not yet been developed. Here we report a comprehensive method to fabricate a dual-gated TI device and demonstrate tuning of the chemical potential of both surfaces across the Dirac points. The most important part of our method is the recipe for safely detaching high-quality, bulk-insulating (Bi<inf>1-x</inf>Sb<inf>x</inf>)<inf>2</inf>Te<inf>3</inf> thin films from sapphire substrates and transferring them to Si/SiO<inf>2</inf> wafers that allow back gating. Fabrication of an efficient top gate by low-temperature deposition of a SiN<inf>x</inf> dielectric complements the procedure. Our dual-gated devices are shown to be effective in tuning the chemical potential in a wide range encompassing the Dirac points on both surfaces.},
   author = {Fan Yang and A. A. Taskin and Satoshi Sasaki and Kouji Segawa and Yasuhide Ohno and Kazuhiko Matsumoto and Yoichi Ando},
   doi = {10.1021/ACSNANO.5B00102},
   issn = {1936086X},
   issue = {4},
   journal = {ACS Nano},
   keywords = {(Bi<inf>1- x</inf>Sb<inf>x</inf>)<inf>2</inf>Te<inf>3</inf>,Dirac fermion,MBE,electrostatic gating,topological insulator},
   month = {4},
   pages = {4050-4055},
   publisher = {American Chemical Society},
   title = {Dual-gated topological insulator thin-film device for efficient fermi-level tuning},
   volume = {9},
   url = {https://pubs.acs.org/doi/full/10.1021/acsnano.5b00102},
   year = {2015}
}
@article{Zhang2010,
   abstract = {Topological insulators in the Bi2 Se3 family have an energy gap in the bulk and a gapless surface state consisting of a single Dirac cone. Low-frequency optical absorption due to the surface state is universally determined by the fine-structure constant. When the thickness of these three-dimensional topological insulators is reduced, they become quasi-two-dimensional insulators with enhanced absorbance. The two-dimensional insulators can be topologically trivial or nontrivial depending on the thickness, and we predict that the optical absorption is larger for topological nontrivial case compared with the trivial case. Since the three-dimensional topological insulator surface state is intrinsically gapless, we propose its potential application in wide bandwidth, high-performance photodetection covering a broad spectrum ranging from terahertz to infrared. The performance of photodetection can be dramatically enhanced when the thickness is reduced to several quintuple layers with a widely tunable band gap depending on the thickness. © 2010 The American Physical Society.},
   author = {Xiao Zhang and Jing Wang and Shou Cheng Zhang},
   doi = {10.1103/PHYSREVB.82.245107/FIGURES/3/MEDIUM},
   issn = {10980121},
   issue = {24},
   journal = {Physical Review B - Condensed Matter and Materials Physics},
   month = {12},
   pages = {245107},
   publisher = {American Physical Society},
   title = {Topological insulators for high-performance terahertz to infrared applications},
   volume = {82},
   url = {https://journals.aps.org/prb/abstract/10.1103/PhysRevB.82.245107},
   year = {2010}
}
@article{Zhao2014,
   abstract = {The topological insulator/normal insulator (TI/NI) superlattices (SLs) with multiple Dirac channels are predicted to offer great opportunity to design novel materials and investigate new quantum phenomena. Here, we report first transport studies on the SLs composed of TI Bi 2 Se 3 layers sandwiched by NI In 2 Se 3 layers artificially grown by molecular beam epitaxy (MBE). The transport properties of two kinds of SL samples show convincing evidence that the transport dimensionality changes from three-dimensional (3D) to two-dimensional (2D) when decreasing the thickness of building block Bi 2 Se 3 layers, corresponding to the crossover from coherent TI transport to separated TI channels. Our findings provide the possibility to realizing "3D surface states" in TI/NI SLs.},
   author = {Yanfei Zhao and Haiwen Liu and Xin Guo and Ying Jiang and Yi Sun and Huichao Wang and Yong Wang and Han-Dong Li and Mao-Hai Xie and Xin-Cheng Xie and Jian Wang},
   doi = {10.1021/nl502220p},
   keywords = {superlattices,topological insulators,transport dimensionality,weak-antilocalization,weak-localization},
   title = {Crossover from 3D to 2D Quantum Transport in {Bi$_2$ Se$_3$ /In$_2$ Se$_3$ }Superlattices},
   url = {https://pubs.acs.org/sharingguidelines},
   year = {2014}
}
@article{Chen2022,
   abstract = {Plasmon polaritons in topological insulators attract attention from a fundamental perspective and for potential THz photonic applications. Although polaritons have been observed by THz far-field spectroscopy on topological insulator microstructures, real-space imaging of propagating THz polaritons has been elusive so far. Here, we show spectroscopic THz near-field images of thin Bi 2 Se 3 layers (prototypical topological insulators) revealing polaritons with up to 12 times increased momenta as compared to photons of the same energy and decay times of about 0.48 ps, yet short propagation lengths. From the images we determine and analyze the polariton dispersion, showing that the polaritons can be explained by the coupling of THz radiation to various combinations of Dirac and massive carriers at the Bi 2 Se 3 surfaces, massive bulk carriers and optical phonons. Our work provides critical insights into the nature of THz polaritons in topological insulators and establishes instrumentation and methodology for imaging of THz polaritons.},
   author = {Shu Chen and Andrei Bylinkin and Zhengtianye Wang and Martin Schnell and Greeshma Chandan and Peining Li and Alexey Y Nikitin and Stephanie Law and Rainer Hillenbrand},
   doi = {10.1038/s41467-022-28791-x},
   issue = {1374},
   journal = {Nature Communications},
   title = {Real-space nanoimaging of THz polaritons in the topological insulator {Bi$_2$ Se$_3$}},
   volume = {13},
   url = {https://doi.org/10.1038/s41467-022-28791-x},
   year = {2022}
}
@article{Vaughan2022,
   abstract = {ARTICLE scitation.org/journal/rsi Directed delivery of terahertz frequency radiation from quantum cascade lasers within a dry 3He dilution refrigerator ABSTRACT We present a scheme for the full integration of terahertz (THz) frequency quantum cascade lasers (QCLs) within a dilution refrigerator in order to provide a directed delivery of THz power into the sample space. We describe a successful operation of a 2.68 THz QCL located on the pulse tube cooler stage of the refrigerator, with its output coupled onto a two-dimensional electron gas (2DEG) located on a milli-kelvin sample stage via hollow metal waveguides and Hysol thermal isolators, achieving a total loss from QCL to the sample of ∼−9 dB. The thermal isolators limit heat leaks to the sample space, with a base temperature of ∼210 mK being achieved. We observe cyclotron resonance (CR) induced in the 2DEG by the QCL and explore the heating impact of the QCL on all stages of the refrigerator. The CR effect induced by the THz QCL is observable at electron temperatures as low as ∼430 mK. The results show a viable route for the exploitation of THz QCLs within the environment of a dilution refrigerator and for the THz power delivery in very low-temperature (<0.5 K) condensed matter experiments.},
   author = {M Vaughan and ; W Michailow and ; M Salih and ; L Li and ; H Beere and D A Ritchie and E H Linfield and ; A G Davies and ; J E Cunningham and W Michailow and M Salih and L Li and H Beere and A G Davies and J E Cunningham},
   doi = {10.1063/5.0102553},
   journal = {Cite as: Rev. Sci. Instrum},
   pages = {113906},
   title = {Directed delivery of terahertz frequency radiation from quantum cascade lasers within a dry 3He dilution refrigerator},
   volume = {93},
   url = {http://creativecommons.org/licenses/by/4.0/},
   year = {2022}
}
@article{Lloyd-Hughes2012,
   abstract = {We review pioneering and recent studies of the conductivity of solid state systems at terahertz frequencies. A variety of theoretical formalisms that describe the terahertz conductivity of bulk, mesoscopic and nanoscale materials are outlined, and their validity and limitations are given. Experimental highlights are discussed from studies of inorganic semiconductors, organic materials (such as graphene, carbon nanotubes and polymers), metallic films and strongly correlated electron systems including superconductors.},
   author = {James Lloyd-Hughes and Tae-In Jeon},
   doi = {10.1007/s10762-012-9905-y},
   journal = {J Infrared Milli Terahz Waves},
   keywords = {Conductivity ·,Semiconductor ·,Superconductor,Terahertz ·},
   pages = {871-925},
   title = {A Review of the Terahertz Conductivity of Bulk and Nano-Materials},
   volume = {33},
   year = {2012}
}
@article{Wu2016,
   abstract = {In this work, we use charge extraction via organic overlayer deposition to lower the chemical potential of topological insulator (TI) Bi2Se3 thin films into the intrinsic (bulk-insulating) regime. We demonstrate the tuning and stabilization of intrinsic topological insulators at high mobility with low-cost organic films. With the protection of the organic charge extraction layers tetrafluorotetracyanoquinodimethane or tris(acetylacetonato)cobalt(III) (Co(acac)3), the sample is stable in the atmosphere with chemical potential ∼135 meV above the Dirac point (85 meV below the conduction band minimum, well within the topological insulator regime) after four months, which is an extraordinary level of environmental stability. The Co complex demonstrates the use of an organometallic for modulating TI charge density. The mobility of surface state electrons is enhanced as high as ∼2000 cm2/V s. Even at room temperature, a true topologically insulating state is realized and stabilized for months' exposure to the atmosphere.},
   author = {Liang Wu and R. M. Ireland and M. Salehi and B. Cheng and N. Koirala and S. Oh and H. E. Katz and N. P. Armitage},
   issn = {00036951},
   issue = {22},
   journal = {Applied Physics Letters},
   month = {5},
   pages = {221603},
   publisher = {American Institute of Physics Inc.},
   title = {Tuning and stabilizing topological insulator {Bi$_2$ Se$_3$} in the intrinsic regime by charge extraction with organic overlayers},
   volume = {108},
   url = {/aip/apl/article/108/22/221603/30480/Tuning-and-stabilizing-topological-insulator},
   year = {2016}
}
@article{Kang2019,
   abstract = {Bi2Te3 - xSex photoconductive detectors are attractive due to their linear photo-response (LPR), potential in ultrabroadband photo-detection, and compatibility with CMOS technology. However, as a fundamental issue for photo-detectors, the weak-light photo-response of Bi2Te3 - xSex detectors was covered by the bolometric response, the photo-thermoelectric effect, and the 300 K background black-body radiation from the optical window. Here, using a window-less system, we systematically measure the weak-light photo-response of a Bi2Te3 photoconductive detector. The bolometric response and photo-thermoelectric effect are carefully excluded. It shows that LPR can persist to a small light power density of P < 10-8W/cm2. Meanwhile, the response is maximized at ∼80 K temperature. We suggest that the LPR is rooted in the unique carrier recombination configuration of Bi2Te3, which can result in a constant lifetime for light-generated carriers. The concerned trap level is manifested by a negative photo-response under reduced light intensity. The signature of surface state related signal is presented as a photo-response with the maximum at ∼10 K temperature, which is fragile under increased light intensity. Although the window-less photo-response measurement is at its early stage, it provides a perspective which is different from that of the traditional optical-window based measurement.},
   author = {Ting Ting Kang and Ping Ping Chen},
   doi = {10.1063/1.5099026/366465},
   issn = {10897550},
   issue = {8},
   journal = {Journal of Applied Physics},
   month = {8},
   pages = {83103},
   publisher = {American Institute of Physics Inc.},
   title = {Bi2Te3 photoconductive detector under weak light},
   volume = {126},
   url = {/aip/jap/article/126/8/083103/366465/Bi2Te3-photoconductive-detector-under-weak-light},
   year = {2019}
}
@article{Ireland2018,
   abstract = {We demonstrate the ability to reduce the carrier concentration of thin films of the topological insulator (TI) Bi2Se3 by utilizing a nonvolatile electrostatic gating via corona charging of electret polymers. Sufficient electric field can be imparted to a polymer-TI bilayer to result in significant electron density depletion, even without the continuous connection of a gate electrode or the chemical modification of the TI. We show that the Fermi level of Bi2Se3 is shifted toward the Dirac point with this method. Using terahertz spectroscopy, we find that the surface chemical potential is lowered into the bulk band gap (approximately 50 meV above the Dirac point and 170 meV below the conduction-band minimum), and it is stabilized in the intrinsic regime while enhancing electron mobility. The mobility of surface state electrons is enhanced to a value as high as approximately 1600 cm2/V s at 5 K.},
   author = {R. M. Ireland and Liang Wu and M. Salehi and S. Oh and N. P. Armitage and H. E. Katz},
   doi = {10.1103/PHYSREVAPPLIED.9.044003/FIGURES/6/MEDIUM},
   issn = {23317019},
   issue = {4},
   journal = {Physical Review Applied},
   month = {4},
   pages = {044003},
   publisher = {American Physical Society},
   title = {Nonvolatile Solid-State Charged-Polymer Gating of Topological Insulators into the Topological Insulating Regime},
   volume = {9},
   url = {https://journals.aps.org/prapplied/abstract/10.1103/PhysRevApplied.9.044003},
   year = {2018}
}
@article{Wu2016-2,
   abstract = {Topological insulators have been proposed to be best characterized as bulk magnetoelectric materials that show response functions quantized in terms of fundamental physical constants. Here, we lower the chemical potential of three-dimensional (3D) Bi2Se3 films to ∼30 meV above the Dirac point and probe their low-energy electrodynamic response in the presence of magnetic fields with high-precision time-domain terahertz polarimetry. For fields higher than 5 tesla, we observed quantized Faraday and Kerr rotations, whereas the dc transport is still semiclassical. A nontrivial Berry's phase offset to these values gives evidence for axion electrodynamics and the topological magnetoelectric effect. The time structure used in these measurements allows a direct measure of the fine-structure constant based on a topological invariant of a solid-state system.},
   author = {Liang Wu and M. Salehi and N. Koirala and J. Moon and S. Oh and N. P. Armitage},
   doi = {10.1126/SCIENCE.AAF5541},
   isbn = {1073310752},
   issn = {10959203},
   issue = {6316},
   journal = {Science},
   month = {12},
   pages = {1124-1127},
   publisher = {American Association for the Advancement of Science},
   title = {Quantized Faraday and Kerr rotation and axion electrodynamics of a 3D topological insulator},
   volume = {354},
   url = {www.sciencemag.org/content/354/6316/1119/suppl/DC1},
   year = {2016}
}
@article{Mondal2018,
   abstract = {Topological insulators have been predicted to exhibit a variety of interesting phenomena including a quantized magnetoelectric response and novel spintronics effects due to spin textures on their surfaces. However, experimental observation of these phenomena has proved difficult due to the finite bulk carrier density which may overwhelm the intrinsic topological responses that are expressed at the surface. Here, we demonstrate an ionic gel gating technique to tune the chemical potential of Bi 2 Se 3 thin films while simultaneously performing THz spectroscopy. We can tune the carrier concentration by an order of magnitude and shift the Fermi energy E F to as low as 10 meV above the Dirac point. At high-bias voltages and magnetic fields, we observe a quantized Faraday angle consistent with the topological magnetoelectric effect that can be tuned by ionic gel gating through a number of plateau states.},
   author = {Mintu Mondal and Dipanjan Chaudhuri and Maryam Salehi and Cheng Wan and N J Laurita and Bing Cheng and Andreas V Stier and Michael A Quintero and Jisoo Moon and Deepti Jain and Pavel P Shibayev and James R Neilson and Seongshik Oh and N P Armitage},
   doi = {10.1103/PhysRevB.98.121106},
   journal = {Physical Review B},
   keywords = {doi:10.1103/PhysRevB.98.121106 url:https://doi.org/10.1103/PhysRevB.98.121106},
   title = {Electric field modulated topological magnetoelectric effect in ${\rm Bi}_{2}{\rm Se}_{3}$},
   volume = {98},
   year = {2018}
}
@article{Autore2017,
   author = {M Autore and P Di Pietro and A Di Gaspare and F D’Apuzzo and F Giorgianni and Matthew Brahlek and Nikesh Koirala and Seongshik Oh and S Lupi},
   doi = {10.1088/1361-648X/aa63ac},
   issn = {0953-8984},
   issue = {18},
   journal = {Journal of Physics: Condensed Matter},
   month = {5},
   pages = {183002},
   title = {Terahertz plasmonic excitations in {Bi$_2$ Se$_3$} topological insulator},
   volume = {29},
   url = {https://iopscience.iop.org/article/10.1088/1361-648X/aa63ac},
   year = {2017}
}
@article{Wang2020,
   abstract = {Topological insulators (TIs) house two-dimensional Dirac plasmons on their surfaces. In TI thin films, plasmons on the top and bottom surfaces couple electrostatically, giving rise to an acoustic and an optical plasmon mode. By extension, a superlattice comprising TI layers and trivially insulating layers could house multiple complex plasmon modes which could be used to create a new type of Dirac metamaterial. In this paper, we synthesize TI superlattices, fabricate them into stripe arrays, characterize their optical and plasmonic properties, and model the samples using transfer matrices. We excite plasmon modes that couple to the phonons in the superlattice, resulting in hybrid plasmon-phonon polaritons. These modes are modeled using an analytical Fano resonance model and the extracted resonant positions are reproduced by transfer matrix modeling. We also excite an epsilon near-zero mode in the top dielectric material (Bi 0.5 In 0.5) 2 Se 3. Understanding the behavior of the polariton modes in this complex system will lend insight into the many-body interaction in low-dimensional systems.},
   author = {Zhengtianye Wang and Theresa P Ginley and Vishnuvardhan Mambakkam and Greeshma Chandan and Yuying Zhang and Chaoying Ni and Stephanie Law},
   doi = {10.1103/PhysRevMaterials.4.115202},
   journal = {PHYSICAL REVIEW MATERIALS},
   keywords = {doi:10.1103/PhysRevMaterials.4.115202 url:https://doi.org/10.1103/PhysRevMaterials.4.115202},
   pages = {115202},
   title = {Plasmon coupling in topological insulator multilayers},
   volume = {4},
   year = {2020}
}
@article{Whitney2017,
   abstract = {We report mid-infrared spectroscopy measurements of ultrathin, electrostatically gated (Bi1-xSbx)2Te3 topological insulator films in which we observe several percent modulation of transmittance and reflectance as gating shifts the Fermi level. Infrared transmittance measurements of gated films were enabled by use of an epitaxial lift-off method for large-area transfer of topological insulator films from infrared-absorbing SrTiO3 growth substrates to thermal oxidized silicon substrates. We combine these optical experiments with transport measurements and angle-resolved photoemission spectroscopy to identify the observed spectral modulation as a gate-driven transfer of spectral weight between both bulk and 2D topological surface channels and interband and intraband channels. We develop a model for the complex permittivity of gated (Bi1-xSbx)2Te3 and find a good match to our experimental data. These results open the path for layered topological insulator materials as a new candidate for tunable, ultrathin infrared optics and highlight the possibility of switching topological optoelectronic phenomena between bulk and spin-polarized surface regimes.},
   author = {William S. Whitney and Victor W. Brar and Yunbo Ou and Yinming Shao and Artur R. Davoyan and D. N. Basov and Ke He and Qi Kun Xue and Harry A. Atwater},
   doi = {10.1021/ACS.NANOLETT.6B03992},
   issn = {15306992},
   issue = {1},
   journal = {Nano Letters},
   keywords = {Bismuth antimony telluride,Burstein-moss shift,Mid-infrared,Optical modulator,Topological insulator,Tunable optical properties},
   month = {1},
   pages = {255-260},
   pmid = {27936794},
   publisher = {American Chemical Society},
   title = {Gate-variable mid-infrared optical transitions in a (Bi1-xSbx)2Te3 topological insulator},
   volume = {17},
   url = {https://pubs.acs.org/doi/full/10.1021/acs.nanolett.6b03992},
   year = {2017}
}
@article{Kim2013,
   abstract = {The photovoltaic and bolometric photoresponse in gapped bilayer graphene was investigated by optical and transport measurements. A pulse coincidence technique at 1.5 μm was used to measure the response times as a function of temperature. The bolometric and photovoltaic response times were found to be identical implying that the photovoltaic response is also governed by hot electron thermal relaxation. Response times of τ∼100-20 ps were found for temperatures from 3-100 K. Above 10 K, the relaxation time was observed to be τ=25±5 ps, independent of temperature within noise. © 2013 American Physical Society.},
   author = {M. H. Kim and J. Yan and R. J. Suess and T. E. Murphy and M. S. Fuhrer and H. D. Drew},
   doi = {10.1103/PHYSREVLETT.110.247402/FIGURES/4/MEDIUM},
   issn = {00319007},
   issue = {24},
   journal = {Physical Review Letters},
   month = {6},
   pages = {247402},
   publisher = {American Physical Society},
   title = {Photothermal response in dual-gated bilayer graphene},
   volume = {110},
   url = {https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.110.247402},
   year = {2013}
}
@article{Autore2015,
   abstract = {The great potential of Dirac electrons for plasmonics and photonics has been readily recognized after their discovery in graphene, followed by applications to smart optical devices. Dirac carriers are also found in topological insulators (TIs)-quantum systems having an insulating gap in the bulk and intrinsic Dirac metallic states at the surface. Here, the plasmonic response of ring structures patterned in Bi2Se3 TI films is investigated through terahertz (THz) spectroscopy. The rings are observed to exhibit a bonding and an antibonding plasmon modes, which we tune in frequency by varying their diameter. An analytical theory based on the THz conductance of unpatterned films is developed, which accurately describes the strong plasmon-phonon hybridization and Fano interference experimentally observed as the bonding plasmon is swiped across the prominent 2 THz phonon exhibited by this material. This work opens the road for the investigation of plasmons in topological insulators and for their application in tunable THz devices. Topological insulator Bi2Se3 microring arrays are investigated by means of terahertz spectroscopy. Both bonding and antibonding plasmon modes are observed in the spectra, together with a strong plasmon-phonon hybridization around 2 THz. An analytical theory is developed, which accurately describes the observed features. This work opens the road for the investigation and design of topological insulators-based plasmonic devices.},
   author = {Marta Autore and Fausto D'Apuzzo and Alessandra Di Gaspare and Valeria Giliberti and Odeta Limaj and Pascale Roy and Matthew Brahlek and Nikesh Koirala and Seongshik Oh and Francisco Javier García de Abajo and Stefano Lupi},
   doi = {10.1002/ADOM.201400513},
   issn = {21951071},
   issue = {9},
   journal = {Advanced Optical Materials},
   keywords = {Dirac fermions,Microrings,Plasmonics,Terahertz,Topological insulators},
   month = {9},
   pages = {1257-1263},
   publisher = {Wiley-VCH Verlag},
   title = {Plasmon-Phonon Interactions in Topological Insulator Microrings},
   volume = {3},
   year = {2015}
}
@article{Nasir2021,
   abstract = {The surface states of the 3D topological insulator (TI), Bi2Se3, are known to host two-dimensional Dirac plasmon polaritons (DPPs) in the terahertz spectral range. In TI thin films, the DPPs excited on the top and bottom surfaces couple, leading to an acoustic mode and an optical plasmon mode. Vertical coupling in these materials is, therefore, reasonably well-understood, but in-plane coupling among localized TI DPPs has yet to be investigated. In this paper, we demonstrate in-plane DPP coupling in TI stripe arrays and show that they exhibit dipole-dipole type coupling. The coupling becomes negligible when the lattice constant is greater than approximately 2.8 times the stripe width, which is comparable to results for in-plane coupling of localized plasmons excited on metallic nanoparticles or graphene plasmon polaritons. This understanding could be leveraged for the creation of TI-based metasurfaces.},
   author = {Saadia Nasir and Zhengtianye Wang and Sivakumar V. Mambakkam and Stephanie Law},
   doi = {10.1063/5.0071895/40520},
   issn = {00036951},
   issue = {20},
   journal = {Applied Physics Letters},
   month = {11},
   pages = {201103},
   publisher = {American Institute of Physics Inc.},
   title = {In-plane plasmon coupling in topological insulator {Bi$_2$ Se$_3$} thin films},
   volume = {119},
   url = {/aip/apl/article/119/20/201103/40520/In-plane-plasmon-coupling-in-topological-insulator},
   year = {2021}
}
@article{Ginley2018,
   abstract = {Topological insulators are predicted to house spin-polarized 2D Dirac plasmons. In topological insulator thin films, Dirac plasmons on the top and bottom surfaces are coupled, giving rise to an unusual dispersion relationship. These plasmons are of interest both for fundamental science as well as applications in terahertz sensing and waveguiding. In this article, conclusive evidence is presented for coupled Dirac plasmons excited in the surface states of topological insulator thin film stripe arrays by investigating how the plasmon frequency depends on both film thickness and stripe width. Bi2Se3 films of thickness 50–200 nm are patterned into periodic stripes of width 1–4 µm to excite plasmons. The plasmon frequency dependence on both film thickness and stripe width is found to be in good agreement with theoretical models for coupling 2D Dirac plasmons. Alternative explanations such as 2D massive plasmons are shown to be inconsistent with data. Finally, effective mode indexes of up to 211 are reported, demonstrating incredible confinement of light in the terahertz frequency range.},
   author = {Theresa P. Ginley and Stephanie Law},
   doi = {10.1002/ADOM.201800113},
   issn = {21951071},
   issue = {13},
   journal = {Advanced Optical Materials},
   keywords = {Dirac plasmons,terahertz plasmonics,topological insulators},
   month = {7},
   publisher = {Wiley-VCH Verlag},
   title = {Coupled Dirac Plasmons in Topological Insulators},
   volume = {6},
   year = {2018}
}
@article{Behner2023,
   abstract = {We present low-temperature magnetotransport measurements on selectively grown Sb2Te3-based topological insulator ring structures. These devices display clear Aharonov-Bohm oscillations in the conductance originating from phase-coherent transport around the ring. The temperature dependence of the oscillation amplitude indicates that the Aharonov-Bohm oscillations originate from ballistic transport along the ring arms. We attribute these oscillations to the topological surface states. Further insight into the phase coherence is gained by comparing with similar Aharonov-Bohm-type oscillations in topological insulator nanoribbons exposed to an axial magnetic field. Here, quasi-ballistic phase-coherent transport is confirmed for closed-loop topological surface states in the transverse direction enclosing the nanoribbon. In contrast, the appearance of universal conductance fluctuations indicates phase-coherent transport in the diffusive regime, which is attributed to bulk carrier transport. Thus, it appears that even in the presence of diffusive p-type charge carriers in Aharonov-Bohm ring structures, phase-coherent quasi-ballistic transport of topological surface states is maintained over long distances.},
   author = {Gerrit Behner and Abdur Rehman Jalil and Dennis Heffels and Jonas Kölzer and Kristof Moors and Jonas Mertens and Erik Zimmermann and Gregor Mussler and Peter Schüffelgen and Hans Lüth and Detlev Grützmacher and Thomas Schäpers},
   doi = {https://doi.org/10.1021/acs.nanolett.3c00905},
   issn = {15306992},
   issue = {14},
   journal = {Nano Letters},
   keywords = {Aharonov-Bohm effect,Topological insulators,ballistic transport,phase-coherent transport,ring interferometer,topological surface states},
   month = {7},
   pages = {6347-6353},
   pmid = {37399545},
   publisher = {American Chemical Society},
   title = {Aharonov-Bohm Interference and Phase-Coherent Surface-State Transport in Topological Insulator Rings},
   volume = {23},
   url = {https://pubs.acs.org/doi/full/10.1021/acs.nanolett.3c00905},
   year = {2023}
}
@article{Huang2024,
   abstract = {Nonvolatile memristors offer a salient platform for artificial neural network (ANN), yet the integration of different function and algorithm blocks into one hardware system remains challenging. Her...},
   author = {Puyang Huang and Xinqi Liu and Yue Xin and Yu Gu and Albert Lee and Yifan Zhang and Zhuo Xu and Peng Chen and Yu Zhang and Weijie Deng and Guoqiang Yu and Di Wu and Zhongkai Liu and Qi Yao and Yumeng Yang and Zhifeng Zhu and Xufeng Kou},
   doi = {10.1021/ACSNANO.4C03278},
   issn = {1936-0851},
   issue = {43},
   journal = {ACS Nano},
   keywords = {anomalous Hall effect,artificial neural network,spin−orbit torque,topological insulator,van der Waals ferromagnet},
   month = {10},
   pages = {29469-29478},
   publisher = {American Chemical Society},
   title = {Integrated Artificial Neural Network with Trainable Activation Function Enabled by Topological Insulator-Based Spin–Orbit Torque Devices},
   volume = {18},
   url = {https://pubs.acs.org/doi/full/10.1021/acsnano.4c03278},
   year = {2024}
}
@article{Wickramasinghe2023,
   abstract = {Three-dimensional topological insulators (3D-TIs) are a new generation of materials with insulating bulk and exotic metallic surface states that facilitate a wide variety of ground-breaking applications. However, utilization of the surface channels is often hampered by the presence of crystal defects, such as antisites, vacancies, and twin domains. For terahertz device applications, twinning is shown to be highly deleterious. Previous attempts to reduce twins using technologically important InP(111) substrates have been promising, but have failed to completely suppress twin domains while preserving high structural quality. Here we report growth of twin-free molecular beam epitaxial Bi2Se3 and Sb2Te3 structures on ultra-thin In2Se3 layers formed by a novel selenium passivation technique during the oxide desorption of smooth, non-vicinal InP(111)B substrates, without the use of an indium source. The formation of un-twinned In2Se3 provides a favorable template to fully suppress twin domains in 3D-TIs, greatly broadening novel device applications in the terahertz regime.},
   author = {Kaushini S. Wickramasinghe and Candice Forrester and Maria C. Tamargo},
   doi = {https://doi.org/10.3390/cryst13040677},
   issn = {20734352},
   issue = {4},
   journal = {Crystals},
   keywords = {3D topological insulators,Antimony Telluride (Sb2Te3),Bismuth Selenide (Bi2Se3),InP(111)B,Indium Selenide (In2Se3),fully twin free,van der Waals materials},
   month = {4},
   pages = {677},
   publisher = {MDPI},
   title = {Molecular Beam Epitaxy of Twin-Free {Bi$_2$Se$_3$} and {Sb$_2$Te$_3$} on {In$_2$Se$_3$/InP(111)B} Virtual Substrates},
   volume = {13},
   url = {https://www.mdpi.com/2073-4352/13/4/677/htm https://www.mdpi.com/2073-4352/13/4/677},
   year = {2023}
}
@article{Liu2021,
   abstract = {We report the temperature dependence of the spin-orbit torque (SOT) in the in situ grown Bi2Te3/MnTe heterostructures by molecular beam epitaxy. By appropriately designing the film stack, robust ferromagnetic order with high Curie temperature and strong perpendicular magnetic anisotropy is established in the MnTe layer. Meanwhile, the sharp hetero-interface warrants highly efficient spin current injection from the conductive topological insulator (TI) channel. Accordingly, SOT-driven magnetization switching is observed up to 90 K with the critical current density within the 106 Acm-2 range. More importantly, the temperature-dependent harmonic measurement data can be divided into two categories, namely, the spin Hall effect of the TI bulk states gives rise to a relatively small spin Hall angle in the high-temperature region, whereas the spin-momentum locking nature of the interfacial Dirac fermions leads to the enhancement of the SOT strength once the topological surface states become the dominant conduction channel at deep cryogenic temperatures. Our results offer direct evidence of the underlying mechanism that determines the SOT efficiency and may set up a suitable platform to realize TI-based spin-orbit applications toward room temperature.},
   author = {Xiaoyang Liu and Di Wu and Liyang Liao and Peng Chen and Yong Zhang and Fenghua Xue and Qi Yao and Cheng Song and Kang L. Wang and Xufeng Kou},
   doi = {10.1063/5.0041062/39494},
   issn = {00036951},
   issue = {11},
   journal = {Applied Physics Letters},
   month = {3},
   publisher = {American Institute of Physics Inc.},
   title = {Temperature dependence of spin - orbit torque-driven magnetization switching in in situ grown {Bi$_2$Te$_3$}/{MnTe} heterostructures},
   volume = {118},
   url = {/aip/apl/article/118/11/112406/39494/Temperature-dependence-of-spin-orbit-torque-driven},
   year = {2021}
}
@article{Haren2024,
   author = {Ryan Van Haren and David Lederman},
   doi = {10.1103/PhysRevB.110.205409},
   issn = {2469-9950},
   issue = {20},
   journal = {Physical Review B},
   month = {11},
   pages = {205409},
   publisher = {American Physical Society},
   title = {Suppressed weak antilocalization in topological insulator–antiferromagnetic insulator {(BiSb)$_2$Te$_3$-MnF$_2$} thin film bilayers},
   volume = {110},
   url = {https://journals.aps.org/prb/abstract/10.1103/PhysRevB.110.205409},
   year = {2024}
}
@article{Kondo2023,
   abstract = {Bismuth selenide (Bi2Se3) epitaxial films were grown at different substrate temperatures (T s) by molecular beam epitaxy. In the optimization of T s, a Bi2Se3 film with the smallest root mean square roughness (Rq) and the lowest electron density was grown at T s = 120 °C. In the optimized growth condition, Bi2Se3 epitaxial films with 3−85 quintuple layers (QL: 1 QL ≈ 1 nm) were grown. In unpolarized Raman spectra, the positions of A 11g and E 2g-modes shifted to the low wavenumbers at film thickness below 10 QL. The polarized Raman spectra showed that the depolarization ratio ρ also changed with film thickness. The change in ρ was more significant than the change in the position shift. This indicates that the measurement of ρ is an effective method to evaluate the thickness of Bi2Se3 ultrathin films.},
   author = {Tomohiro Kondo and Takamu Nozaki and Ryuya Kotabe and Yoshikazu Terai},
   doi = {10.35848/1347-4065/ACAAB3},
   issn = {1347-4065},
   issue = {SD},
   journal = {Japanese Journal of Applied Physics},
   keywords = {Bi2Se3,MBE,thin film},
   month = {1},
   pages = {SD1016},
   publisher = {IOP Publishing},
   title = {Investigation of Raman depolarization ratio in topological insulator {Bi$_2$Se$_3$} epitaxial films},
   volume = {62},
   url = {https://iopscience.iop.org/article/10.35848/1347-4065/acaab3 https://iopscience.iop.org/article/10.35848/1347-4065/acaab3/meta},
   year = {2023}
}
@article{Wang2024,
   abstract = {Hyperbolic metamaterials (HMMs) are engineered materials with a hyperbolic isofrequency surface, enabling a range of interesting phenomena and applications including negative refraction, enhanced sensing, and subdiffraction imaging, focusing, and waveguiding. Existing HMMs primarily work in the visible and infrared spectral range due to the inherent properties of their constituent materials. Here, we demonstrate a THz-range Dirac HMM using topological insulators as the building blocks. We find that the structure houses up to three high-wavevector volume plasmon polariton (VPP) modes, consistent with transfer matrix modeling and effective medium theory calculations. The VPPs have mode indices greater than 100, significantly larger than observed for VPP modes in HMMs made from metals or doped semiconductors while maintaining comparable quality factors. We attribute these properties to the two-dimensional Dirac nature of the electrons occupying the topological insulator surface states. Because these are van der Waals materials, these structures can be grown at a wafer-scale on a variety of substrates, allowing them to be integrated with existing THz structures and enabling next-generation THz optical devices.},
   author = {Zhengtianye Wang and Saadia Nasir and Sathwik Bharadwaj and Yongchen Liu and Sivakumar Vishnuvardhan Mambakkam and Mingyu Yu and Stephanie Law},
   issn = {23304022},
   journal = {ACS Photonics},
   keywords = {metamaterial,terahertz,topological insulator},
   publisher = {American Chemical Society},
   title = {Terahertz Dirac Hyperbolic Metamaterial},
   url = {https://pubs.acs.org/doi/full/10.1021/acsphotonics.4c01004},
   year = {2024}
}
@article{Lippertz2024,
   abstract = {Selective-area epitaxy (SAE) is a useful technique to grow epitaxial films with a desired shape on a prepatterned substrate. Although SAE of patterned topological-insulator (TI) thin films has been performed in the past, there has been no report of SAE-grown TI structures that are bulk-insulating. Here we report the successful growth of Hall-bars and nanowires of bulk-insulating TIs using the SAE technique. Their transport properties show that the quality of the selectively grown structures is comparable to that of bulk-insulating TI films grown on pristine substrates. In SAE-grown TI nanowires, we were able to observe Aharonov-Bohm-like magnetoresistance oscillations that are characteristic of the quantum-confined topological surface states. The availability of bulk-insulating TI nanostructures via the SAE technique opens the possibility to fabricate intricate topological devices in a scalable manner.},
   author = {Gertjan Lippertz and Oliver Breunig and Rafael Fister and Anjana Uday and Andrea Bliesener and Jens Brede and Alexey Taskin and Yoichi Ando},
   doi = {10.1021/ACSAMI.4C06146},
   issn = {19448252},
   issue = {31},
   journal = {ACS Applied Materials and Interfaces},
   keywords = {Aharonov−Bohm oscillations,electrostatic gating,nanowire,selective-area epitaxy,topological insulator},
   month = {8},
   pages = {41293-41299},
   pmid = {39051736},
   publisher = {American Chemical Society},
   title = {Selective-Area Epitaxy of Bulk-Insulating {(Bi$_x$Sb$_{1-x}$)$_2$Te$_3$} Films and Nanowires by Molecular Beam Epitaxy},
   volume = {16},
   year = {2024}
}
@article{Schmitt2022,
   abstract = {The integration of semiconductor Josephson junctions (JJs) in superconducting quantum circuits provides a versatile platform for hybrid qubits and offers a powerful way to probe exotic quasiparticle excitations. Recent proposals for using circuit quantum electrodynamics (cQED) to detect topological superconductivity motivate the integration of novel topological materials in such circuits. Here, we report on the realization of superconducting transmon qubits implemented with (Bi0.06Sb0.94)2Te3topological insulator (TI) JJs using ultrahigh vacuum fabrication techniques. Microwave losses on our substrates, which host monolithically integrated hardmasks used for the selective area growth of TI nanostructures, imply microsecond limits to relaxation times and, thus, their compatibility with strong-coupling cQED. We use the cavity-qubit interaction to show that the Josephson energy of TI-based transmons scales with their JJ dimensions and demonstrate qubit control as well as temporal quantum coherence. Our results pave the way for advanced investigations of topological materials in both novel Josephson and topological qubits.},
   author = {Tobias W. Schmitt and Malcolm R. Connolly and Michael Schleenvoigt and Chenlu Liu and Oscar Kennedy and José M. Chávez-Garcia and Abdur R. Jalil and Benjamin Bennemann and Stefan Trellenkamp and Florian Lentz and Elmar Neumann and Tobias Lindström and Sebastian E. De Graaf and Erwin Berenschot and Niels Tas and Gregor Mussler and Karl D. Petersson and Detlev Grützmacher and Peter Schüffelgen},
   doi = {10.1021/ACS.NANOLETT.1C04055},
   issn = {15306992},
   issue = {7},
   journal = {Nano Letters},
   keywords = {Josephson junctions,selective area growth,stencil lithography,superconducting qubits,topological insulators},
   month = {4},
   pages = {2595-2602},
   pmid = {35235321},
   publisher = {American Chemical Society},
   title = {Integration of Topological Insulator Josephson Junctions in Superconducting Qubit Circuits},
   volume = {22},
   url = {https://pubs.acs.org/doi/full/10.1021/acs.nanolett.1c04055},
   year = {2022}
}
@article{Huang2024,
   abstract = {Nonvolatile memristors offer a salient platform for artificial neural network (ANN), yet the integration of different function and algorithm blocks into one hardware system remains challenging. Her...},
   author = {Puyang Huang and Xinqi Liu and Yue Xin and Yu Gu and Albert Lee and Yifan Zhang and Zhuo Xu and Peng Chen and Yu Zhang and Weijie Deng and Guoqiang Yu and Di Wu and Zhongkai Liu and Qi Yao and Yumeng Yang and Zhifeng Zhu and Xufeng Kou},
   doi = {10.1021/ACSNANO.4C03278},
   issn = {1936-0851},
   issue = {43},
   journal = {ACS Nano},
   keywords = {anomalous Hall effect,artificial neural network,spin−orbit torque,topological insulator,van der Waals ferromagnet},
   month = {10},
   pages = {29469-29478},
   publisher = {American Chemical Society},
   title = {Integrated Artificial Neural Network with Trainable Activation Function Enabled by Topological Insulator-Based Spin–Orbit Torque Devices},
   volume = {18},
   url = {https://pubs.acs.org/doi/full/10.1021/acsnano.4c03278},
   year = {2024}
}
@article{Breunig2021,
   abstract = {Topological insulators (TIs) hold promise as a platform for unique quantum phenomena. However, realizing these phenomena experimentally requires sophisticated devices. In this Technical Review, we discuss four topics of particular interest for TI devices: topological superconductivity, quantum anomalous Hall insulators as a platform for exotic phenomena, spintronic functionalities and topological mesoscopic physics. We also discuss the status and technical challenges in fabricating TI devices to address new physics. Topological insulators are unique materials giving rise to unconventional quantum phenomena. This Technical Review discusses how various physics effects can only be observed in devices carefully fabricated to address them, including topological superconductivity, quantum anomalous Hall states, spintronic functionalities and topological mesoscopic physics.},
   author = {Oliver Breunig and Yoichi Ando},
   doi = {10.1038/s42254-021-00402-6},
   issn = {2522-5820},
   issue = {3},
   journal = {Nature Reviews Physics},
   keywords = {Design,Electronic devices,Superconducting devices,Topological insulators,synthesis and processing},
   month = {12},
   pages = {184-193},
   publisher = {Nature Publishing Group},
   title = {Opportunities in topological insulator devices},
   volume = {4},
   url = {https://www.nature.com/articles/s42254-021-00402-6},
   year = {2021}
}
@article{Wang2021,
   abstract = {The naturally existing chalcogenide Bi2Se3 is topologically nontrivial due to the band inversion caused by the strong spin-orbit coupling inside the bulk of the material. The surface states are spin polarized, protected by the time-inversion symmetry, and thus robust to the scattering caused by nonmagnetic defects. A high-purity topological insulator thin film can be easily grown via molecular beam epitaxy (MBE) on various substrates to enable novel electronics, optics, and spintronics applications. However, the unique surface state properties have historically been limited by the film quality, which is evaluated by crystallinity, surface morphology, and transport data. Here we propose and investigate different MBE growth strategies to improve the quality of Bi2Se3 thin films grown by MBE. Based on the surface passivation status, we have classified the substrates into two categories, self-passivated or unpassivated, and determine the optimal growth mechanisms on the representative sapphire and GaAs, respectively. For Bi2Se3 on GaAs, the surface passivation status determines the dominant growth mechanism. In the end, growths of the topological trivial insulator (Bi0.5In0.5)2Se3 (BIS) on GaAs are investigated following the protocols proposed.},
   author = {Zhengtianye Wang and Stephanie Law},
   doi = {10.1021/ACS.CGD.1C00663},
   issn = {15287505},
   issue = {12},
   journal = {Crystal Growth and Design},
   month = {12},
   pages = {6752-6765},
   publisher = {American Chemical Society},
   title = {Optimization of the Growth of the Van der Waals Materials {Bi$_2$Se$_3$} and {(Bi$_{0.5}$In$_{0.5}$)$_2$Se$_3$} by Molecular Beam Epitaxy},
   volume = {21},
   year = {2021}
}
@article{Koirala2015,
   abstract = {Material defects remain as the main bottleneck to the progress of topological insulators (TIs). In particular, efforts to achieve thin TI samples with dominant surface transport have always led to increased defects and degraded mobilities, thus making it difficult to probe the quantum regime of the topological surface states. Here, by utilizing a novel buffer layer scheme composed of an In2Se3/(Bi0.5In0.5)2Se3 heterostructure, we introduce a quantum generation of Bi2Se3 films with an order of magnitude enhanced mobilities than before. This scheme has led to the first observation of the quantum Hall effect in Bi2Se3.},
   author = {Nikesh Koirala and Matthew Brahlek and Maryam Salehi and Liang Wu and Jixia Dai and Justin Waugh and Thomas Nummy and Myung Geun Han and Jisoo Moon and Yimei Zhu and Daniel Dessau and Weida Wu and N. Peter Armitage and Seongshik Oh},
   doi = {10.1021/ACS.NANOLETT.5B03770},
   issn = {15306992},
   issue = {12},
   journal = {Nano Letters},
   keywords = {Topological insulator,heterostructure,molecular beam epitaxy,quantum Hall effect,thin films},
   month = {12},
   pages = {8245-8249},
   publisher = {American Chemical Society},
   title = {Record Surface State Mobility and Quantum Hall Effect in Topological Insulator Thin Films via Interface Engineering},
   volume = {15},
   url = {https://pubs.acs.org/doi/full/10.1021/acs.nanolett.5b03770},
   year = {2015}
}
@article{Yoshimi2015,
   abstract = {The three-dimensional topological insulator is a novel state of matter characterized by two-dimensional metallic Dirac states on its surface. To verify the topological nature of the surface states, Bi-based chalcogenides such as Bi2Se3, Bi2Te3, Sb2Te3 and their combined/mixed compounds have been intensively studied. Here, we report the realization of the quantum Hall effect on the surface Dirac states in (Bi1−xSbx)2Te3 films. With electrostatic gate-tuning of the Fermi level in the bulk band gap under magnetic fields, the quantum Hall states with filling factor ±1 are resolved. Furthermore, the appearance of a quantum Hall plateau at filling factor zero reflects a pseudo-spin Hall insulator state when the Fermi level is tuned in between the energy levels of the non-degenerate top and bottom surface Dirac points. The observation of the quantum Hall effect in three-dimensional topological insulator films may pave a way toward topological insulator-based electronics. Three-dimensional topological insulators are materials that are nonmagnetic insulators in the bulk but exhibit metallic surface states. Yoshimi et al, now identify a signature of such two-dimensional states, the quantum Hall effect, in bismuth-based chalcogenide topological insulators.},
   author = {R. Yoshimi and A. Tsukazaki and Y. Kozuka and J. Falson and K. S. Takahashi and J. G. Checkelsky and N. Nagaosa and M. Kawasaki and Y. Tokura},
   doi = {10.1038/ncomms7627},
   issn = {2041-1723},
   issue = {1},
   journal = {Nature Communications},
   keywords = {Applied physics,Quantum Hall,Surfaces,Topological matter,interfaces and thin films},
   month = {4},
   pages = {1-6},
   publisher = {Nature Publishing Group},
   title = {Quantum Hall effect on top and bottom surface states of topological insulator {(Bi$_{1−x}$Sb$_x$)$_2$Te$_3$} films},
   volume = {6},
   url = {https://www.nature.com/articles/ncomms7627},
   year = {2015}
}
@article{Rimoldi2020,
   abstract = {Antimony telluride (Sb2Te3) thin films were prepared by a room temperature Metal-Organic Chemical Vapor Deposition (MOCVD) process using antimony chloride (SbCl3) and bis(trimethylsilyl)telluride (Te(SiMe3)2) as precursors. Pre-growth and post-growth treatments were found to be pivotal in favoring out-of-plane and in-plane alignment of the crystallites composing the films. A comprehensive suite of characterization techniques were used to evaluate their composition, surface roughness, as well as to assess their morphology, crystallinity, and structural features, revealing that a quick post-growth annealing triggers the formation of epitaxial-quality Sb2Te3films on Si(111).},
   author = {Martino Rimoldi and Raimondo Cecchini and Claudia Wiemer and Alessio Lamperti and Emanuele Longo and Lucia Nasi and Laura Lazzarini and Roberto Mantovan and Massimo Longo},
   doi = {10.1039/D0RA02567D},
   issn = {20462069},
   issue = {34},
   journal = {RSC Advances},
   month = {5},
   pages = {19936-19942},
   publisher = {Royal Society of Chemistry},
   title = {Epitaxial and large area {Sb$_2$Te$_3$} thin films on silicon by MOCVD},
   volume = {10},
   url = {https://pubs.rsc.org/en/content/articlehtml/2020/ra/d0ra02567d https://pubs.rsc.org/en/content/articlelanding/2020/ra/d0ra02567d},
   year = {2020}
}
@article{Witting2019,
   abstract = {Bismuth telluride is the working material for most Peltier cooling devices and thermoelectric generators. This is because Bi2Te3 (or more precisely its alloys with Sb2Te3 for p-type and Bi2Se3 for n-type material) has the highest thermoelectric figure of merit, zT, of any material around room temperature. Since thermoelectric technology will be greatly enhanced by improving Bi2Te3 or finding a superior material, this review aims to identify and quantify the key material properties that make Bi2Te3 such a good thermoelectric. The large zT can be traced to the high band degeneracy, low effective mass, high carrier mobility, and relatively low lattice thermal conductivity, which all contribute to its remarkably high thermoelectric quality factor. Using literature data augmented with newer results, these material parameters are quantified, giving clear insight into the tailoring of the electronic band structure of Bi2Te3 by alloying, or reducing thermal conductivity by nanostructuring. For example, this analysis clearly shows that the minority carrier excitation across the small bandgap significantly limits the thermoelectric performance of Bi2Te3, even at room temperature, showing that larger bandgap alloys are needed for higher temperature operation. Such effective material parameters can also be used for benchmarking future improvements in Bi2Te3 or new replacement materials.},
   author = {Ian T. Witting and Thomas C. Chasapis and Francesco Ricci and Matthew Peters and Nicholas A. Heinz and Geoffroy Hautier and G. Jeffrey Snyder},
   doi = {10.1002/AELM.201800904},
   issn = {2199-160X},
   issue = {6},
   journal = {Advanced Electronic Materials},
   keywords = {bismuth telluride,electronic structures,thermoelectrics,transport modeling},
   month = {6},
   pages = {1800904},
   publisher = {John Wiley \& Sons, Ltd},
   title = {The Thermoelectric Properties of Bismuth Telluride},
   volume = {5},
   url = {https://onlinelibrary.wiley.com/doi/full/10.1002/aelm.201800904 https://onlinelibrary.wiley.com/doi/abs/10.1002/aelm.201800904 https://onlinelibrary.wiley.com/doi/10.1002/aelm.201800904},
   year = {2019}
}
@article{Abdellaoui2019,
   abstract = {Defects such as planar faults in thermoelectric materials improve their performance by scattering phonons with short and medium mean free paths (3–100 nm), thereby reducing the lattice thermal conductivity,κl. Understanding statistically the microscopic distribution of these extended defects within the grains and in low angle grain boundaries is necessary to tailor and develop materials with optimal thermoelectric performance for waste heat harvesting. Herein, we analyze these defects from the millimeter down to the nanometer scale in a AgSbTe2 thermoelectric material with low angle grain boundaries. The investigations were performed using electron channeling contrast imaging combined with transmission electron microscopy. The microstructure study was complemented by estimating the effect of planar faults on the phonon scattering using the Debye-Callaway model. AgSbTe2 is a promising thermoelectric material, which exhibits extremely low thermal conductivity, κ, of 0.5 Wm−1K−1 at room temperature. In contrast to conventional alloys or intermetallic materials, in the present material small angle grain boundaries are not composed of individual dislocations but of a dense arrangement of stacked planar faults with fault densities up to NPF=1.6⋅108m−1. We explain their abundance based on their low interfacial energy of about 186 mJm−2 calculated ab-initio. The current findings show, that it is possible to reach very high densities of phonon-scattering planar faults by the correct microstructure engineering in AgSbTe2 thermoelectric materials.},
   author = {L. Abdellaoui and Siyuan Zhang and Stefan Zaefferer and R. Bueno-Villoro and Andrei Baranovskiy and Oana Cojocaru-Mirédin and Yuan Yu and Y. Amouyal and D. Raabe and Gerald Jeffrey Snyder and Christina Scheu},
   doi = {10.1016/J.ACTAMAT.2019.07.031},
   issn = {1359-6454},
   journal = {Acta Materialia},
   keywords = {Electron microscopy,Planar faults,Silver-antimony-telluride compounds,Thermal conductivity,Thermoelectric materials},
   month = {10},
   pages = {135-145},
   publisher = {Pergamon},
   title = {Density, distribution and nature of planar faults in silver antimony telluride for thermoelectric applications},
   volume = {178},
   year = {2019}
}
@article{daSilva2004,
   abstract = {The flows of heat and electricity in a column-type micro-thermoelectric cooler are analyzed by modeling the various interfacial resistances. Electron (barrier tunneling) and phonon (diffuse mismatch) boundary resistances at the thermoelectric/metal interface, and thermal non-equilibrium between electrons and phonons adjacent to this interface (cooling length), increase the thermal conduction resistance and decrease the Seebeck coefficient of the thermoelectric elements. These in turn reduce the device cooling performance, which is also affected by the thermal and electrical contact resistances at the thermoelectric/metal and metal/electrical-insulator interfaces.To produce a temperature drop of 10 K with a cooling load of 10 mW, the optimum number of thermoelement pairs, operating current, and coefficient of performance, based on vapor deposited 4 μm thick films of Bi2Te3 and Sb2Te3, are predicted for a micro-thermoelectric cooler operating with a 3 V battery. © 2003 Elsevier Ltd. All rights reserved.},
   author = {Luciana W. da Silva and Massoud Kaviany},
   doi = {10.1016/J.IJHEATMASSTRANSFER.2003.11.024},
   issn = {0017-9310},
   issue = {10-11},
   journal = {International Journal of Heat and Mass Transfer},
   month = {5},
   pages = {2417-2435},
   publisher = {Pergamon},
   title = {Micro-thermoelectric cooler: interfacial effects on thermal and electrical transport},
   volume = {47},
   year = {2004}
}
@article{Zheng2015,
   abstract = {To investigate the effect of strain on specific heat, sound velocity and lattice thermal conductivity of nanocrystalline bismuth antimony telluride thin films, we performed both experimental study and modeling. The nanocrystalline thin films had mostly preferred crystal orientation along c-axis, and strains in the both directions of c-axis and a-b-axis. It was found that the thermal conductivity of nanocrystalline thin films decreased greatly as compared with that of bulk alloys. To gain insight into the thermal transport in the strained nanocrystalline thin films, we estimated the lattice thermal conductivity based on the phonon transport model of full distribution of mean free paths accounting for the effects of grain size and strain which was influenced to both the sound velocity and the specific heat. As a result, the lattice thermal conductivity was increased when the strain was shifted from compressive to tensile direction. We also confirmed that the strain was influenced by the lattice thermal conductivity but the reduction of the lattice thermal conductivity of thin films can be mainly attributed to the nano-size effect rather than the strain effect. Finally, it was found that the measured lattice thermal conductivities were in good agreement with modeling.},
   author = {D. Zheng and S. Tanaka and K. Miyazaki and M. Takashiri},
   doi = {10.1007/S11664-014-3518-2},
   issn = {03615235},
   issue = {6},
   journal = {Journal of Electronic Materials},
   keywords = {Strain,bismuth antimony telluride,crystal orientation,lattice thermal conductivity,nanocrystalline},
   month = {6},
   pages = {1679-1687},
   publisher = {Springer New York LLC},
   title = {Evaluation of Specific Heat, Sound Velocity and Lattice Thermal Conductivity of Strained Nanocrystalline Bismuth Antimony Telluride Thin Films},
   volume = {44},
   url = {https://link.springer.com/article/10.1007/s11664-014-3518-2},
   year = {2015}
}
@article{Bardeen1950,
   abstract = {The method of effective mass, extended to apply to gradual shifts in energy bands resulting from deformations of the crystal lattice, is used to estimate the interaction between electrons of thermal energy and the acoustical modes of vibration. The mobilities of electrons and holes are thus related to the shifts of the conduction and valence-bond (filled) bands, respectively, associated with dilations of longitudinal waves. The theory is checked by comparison of the sum of the shifts of the conduction and valence-bond bands, as derived from the mobilities, with the shift of the energy gap with dilation. The latter is obtained independently for silicon, germanium and tellurium from one or more of the following: (1) the change in intrinsic conductivity with pressure, (2) the change in resistance of an n-p junction with pressure, and (3) the variation of intrinsic concentration with temperature and the thermal expansion coefficient. Higher mobilities of electrons and holes in germanium as compared with silicon are correlated with a smaller shift of energy gap with dilation. © 1950 The American Physical Society.},
   author = {J. Bardeen and W. Shockley},
   doi = {10.1103/PhysRev.80.72},
   issn = {0031899X},
   issue = {1},
   journal = {Physical Review},
   month = {10},
   pages = {72},
   publisher = {American Physical Society},
   title = {Deformation Potentials and Mobilities in Non-Polar Crystals},
   volume = {80},
   url = {https://journals.aps.org/pr/abstract/10.1103/PhysRev.80.72},
   year = {1950}
}
@article{Farid2005,
   abstract = {Sb2Te3 films of different thicknesses, in the thickness range 300-620 nm, were prepared by thermal evaporation. X-ray analysis showed that the as-deposited Sb2Te3 films are amorphous while the source powder and annealed films showed a polycrystalline nature. The AC conductivity and dielectric properties of Sb2Te 3 films have been investigated in the frequency range 0.4-100 kHz and temperature range 303-373 K. The AC conductivity σ AC(ω) was found to obey the power law ωs where s≤1 independent of film thickness. The temperature dependence of both AC conductivity and the exponent s can be reasonably well interpreted by the correlated barrier hopping (CBH) model. The experimental results of the dielectric constant ε1 and the dielectric loss ε 2 are frequency and temperature dependent and thickness independent. The maximum barrier height WM calculated from dielectric measurements according to the Guintini equation agrees with that proposed by the theory of hopping of charge carriers over a potential barrier as suggested by Elliott for chalcogenide glasses. The effect of annealing at different temperatures on the AC conductivity and dielectric properties was also investigated. Values of σAC, ε1 and ε 2 were found to increase with annealing treatment due to the increase of the degree of ordering of the investigated films. The Cole-Cole plots for the as-deposited and annealed Sb2Te3 films have been used to determined the molecular relaxation time τ. The temperature dependence of τ indicates a thermally activated process. © 2005 Published by Elsevier Ltd.},
   author = {A. M. Farid and H. E. Atyia and N. A. Hegab},
   doi = {10.1016/J.VACUUM.2005.05.003},
   issn = {0042-207X},
   issue = {4},
   journal = {Vacuum},
   keywords = {Conductivity of semiconductors,Dielectric of Sb 2Te3 thin films,Electrical properties},
   month = {10},
   pages = {284-294},
   publisher = {Pergamon},
   title = {AC conductivity and dielectric properties of Sb2Te3 thin films},
   volume = {80},
   year = {2005}
}
@article{Zeng2018,
   abstract = {Indium selenide (InSe) has attracted tremendous research interest due to its high mobility and potential applications in next-generation electronics. However, the underlying transport mechanism of carriers in thin InSe at low temperatures remains unknown. Here we report the gate voltage and temperature-dependent magnetotransport properties of γ-InSe transistor devices with Hall mobility up to 2455cm2V-1s-1 at the temperature of 1.7 K. We observe a gate-tunable weak antilocalization behavior at lower magnetic field B, which shows a transition to weak localization at higher B region. We find that the magnetotransport data agree well with the Hikami-Larkin-Nagaoka theory. The conductivity and temperature dependence of phase-coherence length reveal that the electron-electron (e-e) interactions are dominated dephasing mechanism for electronic transport in γ-InSe at low temperatures. The maximum phase-coherence length is found to be 320 nm at 1.7 K, larger than that of monolayer MoS2 and few-layer black phosphorus. These results enrich the fundamental understanding of electronic transport properties of InSe.},
   author = {Junwen Zeng and Shi Jun Liang and Anyuan Gao and Yu Wang and Chen Pan and Chenchen Wu and Erfu Liu and Lili Zhang and Tianjun Cao and Xiaowei Liu and Yajun Fu and Yiping Wang and Kenji Watanabe and Takashi Taniguchi and Haizhou Lu and Feng Miao},
   doi = {10.1103/PHYSREVB.98.125414},
   issn = {24699969},
   issue = {12},
   journal = {Physical Review B},
   month = {9},
   pages = {125414},
   publisher = {American Physical Society},
   title = {Gate-tunable weak antilocalization in a few-layer {InSe}},
   volume = {98},
   url = {https://journals.aps.org/prb/abstract/10.1103/PhysRevB.98.125414},
   year = {2018}
}
@article{Hikami1980,
   abstract = {Effect of the spin-orbit interaction is studied for the random potential scattering in two dimensions by the renormalization group method. It is shown that the behaviors are in the three types depending on the symmetry. The recent observation of classified the negative magnetoresistance of MOSFET different is},
   author = {Shinobu Hikami and Anatoly I. Larkin and Yosuke Nagaoka},
   doi = {10.1143/PTP.63.707},
   issn = {0033-068X},
   issue = {2},
   journal = {Progress of Theoretical Physics},
   month = {2},
   pages = {707-710},
   publisher = {Oxford Academic},
   title = {Spin-Orbit Interaction and Magnetoresistance in the Two Dimensional Random System},
   volume = {63},
   url = {https://dx.doi.org/10.1143/PTP.63.707},
   year = {1980}
}
@article{Li2022,
   abstract = {We report an experimental study of the effect of coherent surface-bulk electron scattering on quantum transport in a three-dimensional topological insulator Bi2Te3 nanoplate. The nanoplate is grown via van der Waals epitaxy on a mica substrate and a top-gated Hall-bar device is fabricated from the nanoplate directly on the growth substrate. Top-gate voltage dependent measurements of the sheet resistance of the device reveal that the transport carriers in the nanoplate are of n-type and that, with decreasing top gate voltage, the carrier density in the nanoplate is decreased. However, the mobility is increased with decreasing top-gate voltage. This mobility increase with decreasing carrier density in the nanoplate is demonstrated to arise from a decrease in bulk-to-surface electron scattering rate. Low-field magnetotransport measurements are performed at low temperatures. The measured magnetoconductivity of the nanoplate shows typical weak anti-localization (WAL) characteristics. We analyze the measurements by taking surface-bulk inter-channel electron scattering into account and extract dephasing times τφ, diffusion coefficients D of electrons at the top surface and in the bulk, and the surface-bulk scattering times τSB as a function of top-gate voltage and temperature. It is found that the dephasing in the nanoplate arises dominantly from electron–electron scattering with small energy transfers. It is also found that the ratio of τφ/τSB (a measure of the surface-bulk electron coherent coupling) is decreased with decreasing gate voltage or increasing temperature. We demonstrate that taking the surface-bulk coherent electron scattering in our Bi2Te3 nanoplate into account is essential to understand quantum transport measurements at low temperatures.},
   author = {Xiaobo Li and Mengmeng Meng and Shaoyun Huang and Congwei Tan and Congcong Zhang and Hailin Peng and H. Q. Xu},
   doi = {10.1039/D1NR08054G},
   issn = {2040-3372},
   issue = {7},
   journal = {Nanoscale},
   month = {2},
   pages = {2586-2592},
   pmid = {35132985},
   publisher = {The Royal Society of Chemistry},
   title = {Surface-bulk coupling in a {Bi$_2$Te$_3$} nanoplate grown by van der Waals epitaxy},
   volume = {14},
   url = {https://pubs.rsc.org/en/content/articlehtml/2022/nr/d1nr08054g https://pubs.rsc.org/en/content/articlelanding/2022/nr/d1nr08054g},
   year = {2022}
}
@article{Gopal2017,
   abstract = {The surface states of a 3D topological insulator (TI) exhibit topological protection against backscattering. However, the contribution of bulk electrons to the transport data is an impediment to the topological protection of surface states. We report the tuning of the chemical potential in the bulk in Bi2Se2Te TI thin films, pinning it near the center of the bulk band gap, thereby suppressing the bulk carriers. The temperature dependent resistance of these films show activated behavior down to 50 K, followed by a metallic transition at lower temperatures, a hallmark of robustness of TI surface states. Manifestation of topological protection and surface dominated transport is explained by 2D weak antilocalization phenomenon. We further explore the effect of surface to bulk coupling in TI in this work, which is captured by the number of effective conducting surface channels that participate in the transport. The presence of a single conducting channel indicates a strong surface to bulk coupling which is detrimental to purely topological transport. We demonstrate the decoupling of topological surface states on opposite surfaces of thin films, thereby suppressing the bulk transport. Our findings provide a deeper understanding of surface to bulk coupling along with topological transport behavior and their respective tunability.},
   author = {Radha Krishna Gopal and Sourabh Singh and Arpita Mandal and Jit Sarkar and Chiranjib Mitra},
   doi = {10.1038/s41598-017-04458-2},
   issn = {2045-2322},
   issue = {1},
   journal = {Scientific Reports},
   keywords = {Surfaces,Topological matter,interfaces and thin films},
   month = {7},
   pages = {1-10},
   pmid = {28687773},
   publisher = {Nature Publishing Group},
   title = {Topological delocalization and tuning of surface channel separation in {Bi$_2$Se$_2$Te} Topological Insulator Thin films},
   volume = {7},
   url = {https://www.nature.com/articles/s41598-017-04458-2},
   year = {2017}
}
@article{Lensch-Falk2012,
   abstract = {Electrodeposition is a promising low-cost method to fabricate nanostructured thermoelectric thin films such as Sb 2Te 3. However, electrodeposition of crystalline Sb 2Te 3 without the need for additional processing and with good compositional control has presented a challenge. Here we report on the electrodeposition of crystalline Sb 2Te 3 thin films at room temperature from a tartaric-nitric acid electrolyte using a pulsed, potentiostatic process. The effects of synthesis conditions on the resulting microstructure and compositional homogeneity are investigated using x-ray diffraction, electron diffraction, electron microscopy, and energy dispersive x-ray spectroscopy. The composition of the Sb-Te films was found to be dependent on the interval between pulses, a result that is likely due to the slow kinetics associated with Sb 2Te 3 formation at the surface. We also observed a change in texture and microstructure with varied applied pulse duration: for short pulse durations a lamellar microstructure with a {000>} texture forms, whereas for longer pulse durations a more equiaxed and randomly oriented microstructure forms. The thermal conductivities of the pulsed electrodeposited films are surprisingly low at less than 2 W/K·m and are found to systematically decrease with reduced pulse time. © 2012 Elsevier B.V. All rights reserved.},
   author = {J. L. Lensch-Falk and D. Banga and P. E. Hopkins and D. B. Robinson and V. Stavila and P. A. Sharma and D. L. Medlin},
   doi = {10.1016/J.TSF.2012.05.078},
   issn = {0040-6090},
   issue = {19},
   journal = {Thin Solid Films},
   keywords = {Electrochemical deposition,Microstructure,Thermal conductivity,Thermoelectrics,Transmission electron microscopy},
   month = {7},
   pages = {6109-6117},
   publisher = {Elsevier},
   title = {Electrodeposition and characterization of nano-crystalline antimony telluride thin films},
   volume = {520},
   year = {2012}
}
@article{Richardella2015,
   abstract = {We describe the characterization of structural defects that occur during molecular beam epitaxy of topological insulator thin films on commonly used substrates. Twinned domains are ubiquitous but can be reduced by growth on smooth InP (111)A substrates, depending on details of the oxide desorption. Even with a low density of twins, the lattice mismatch between (Bi, Sb)2Te3 and InP can cause tilts in the film with respect to the substrate. We also briefly discuss transport in simultaneously top and back electrically gated devices using SrTiO3 and the use of capping layers to protect topological insulator films from oxidation and exposure.},
   author = {Anthony Richardella and Abhinav Kandala and Joon Sue Lee and Nitin Samarth},
   doi = {https://doi.org/10.1063/1.4926455},
   issn = {2166532X},
   issue = {8},
   journal = {APL Materials},
   month = {8},
   publisher = {American Institute of Physics Inc.},
   title = {Characterizing the structure of topological insulator thin films},
   volume = {3},
   url = {/aip/apm/article/3/8/083303/120634/Characterizing-the-structure-of-topological},
   year = {2015}
}
@article{Rouillard1995,
   abstract = {We have conducted studies on the use of a cracker cell for antimony generating Sb2 molecules. For GaSb GaSb epilayers, compared with the ones produced with a traditional cell generating Sb4 molecules, the use of the cracker cell has allowed two remarkable improvements: The most impressive one is the optical quality as displayed by photoluminescence at 2 K. We present in particular a spectrum with a BE4 excitonic line of full width at half maximum equal to 1.7 meV, which is, in our knowledge, the best reported value in the field of MBE. The other is the higher crystallographic quality: GaSb epilayers made from Sb4 surprisingly did not match the GaSb substrate. We showed that this mismatch could be attributed to arsenic coming from a film deposited on the surroundings of the antimony cell during previous arsenide growth. The continuous heating of the cracker tube (at a stand-by temperature of 700°C) caused the sublimation and the total disappearance of the film of arsenic. Epilayers made with the "clean" cracker cell match the substrate and have 004 diffraction peaks with a FWHM of 12″ which is the typical value given by bare substrates. © 1995.},
   author = {Y. Rouillard and B. Lambert and Y. Toudic and M. Baudet and M. Gauneau},
   doi = {10.1016/0022-0248(95)00271-5},
   issn = {0022-0248},
   issue = {1-2},
   journal = {Journal of Crystal Growth},
   month = {11},
   pages = {30-38},
   publisher = {North-Holland},
   title = {On the use of dimeric antimony in molecular beam epitaxy},
   volume = {156},
   year = {1995}
}
@article{Xie1999,
   abstract = {In this paper, we report on the electrical and optical properties of undoped GaSb samples grown by MBE using Sb1 as well as Sb2 produced in a conventional antimony cracker. We establish the existence of Sb1 and then extract the mole fraction of Sb1 in the antimony beam as a function of the cracking zone temperature based on a combined analysis of mass spectrometry data and ion gauge flux reading. We find that the Sb1 mole fraction becomes greater than 90% for cracking zone temperature above 950 °C. A series of undoped GaSb samples are grown over a wide range of substrate temperature, V/III ratio and cracking zone temperature. The undoped GaSb samples grown at 550 °C show p-type conductivity with a room-temperature hole mobility and hole concentration of approximately 730 cm2 v-1 s-1 and approximately 3×1016 cm-3, respectively. The hole mobility and hole concentration are essentially independent of the V/III ratio over a range of 1.2-4. Decreasing the growth temperature to 440 °C leads to a simultaneous decrease in hole mobility, residual hole concentration and photoluminescence intensity. Hole mobility and hole concentration do not depend strongly on the cracking zone temperature in the range 790-1000 °C; however, the optical intensity of the samples grown using Sb1 is approximately one order of magnitude stronger than those using Sb2. Besides the commonly seen bound exciton transitions at 805 (BE1), 803 (BE2), 800 (BE3) and 796 meV (BE4), a free exciton transition at approximately 809.4 meV (4 K) is observed in the samples grown with Sb1 at 550 °C, indicating a greatly reduced density of nonradiative recombination centers.},
   author = {Qianghua Xie and J. E. Van Nostrand and R. L. Jones and J. Sizelove and D. C. Look},
   doi = {10.1016/S0022-0248(99)00379-6},
   issn = {0022-0248},
   issue = {4},
   journal = {Journal of Crystal Growth},
   month = {12},
   pages = {255-265},
   publisher = {North-Holland},
   title = {Electrical and optical properties of undoped {GaSb} grown by molecular beam epitaxy using cracked {Sb1} and {Sb2}},
   volume = {207},
   year = {1999}
}
@article{Moore2009,
   abstract = {Spin–orbit coupling in some materials leads to the formation of surface states that are topologically protected from scattering. Theory and experiments have found an important new family of such materials.},
   author = {Joel Moore},
   doi = {10.1038/nphys1294},
   issn = {1745-2481},
   issue = {6},
   journal = {Nature Physics},
   keywords = {Atomic,Classical and Continuum Physics,Complex Systems,Condensed Matter Physics,Mathematical and Computational Physics,Molecular,Optical and Plasma Physics,Physics,Theoretical,general},
   pages = {378-380},
   publisher = {Nature Publishing Group},
   title = {The next generation},
   volume = {5},
   url = {https://www.nature.com/articles/nphys1294},
   year = {2009}
}
@article{Xia2009,
   abstract = {Topological insulators are exotic states of matter that show quantum-Hall-like behaviour in the absence of a magnetic field. Surface states in such systems are protected against scattering and are thought to provide an avenue for the realization of fault-tolerant quantum computing. Experiments now reveal the observation of such a topological state of matter in Bi2Se3, a naturally occurring stoichiometric material with a simple surface-state structure and a bulk energy gap larger than kBT at room temperature. Recent experiments and theories have suggested that strong spin–orbit coupling effects in certain band insulators can give rise to a new phase of quantum matter, the so-called topological insulator, which can show macroscopic quantum-entanglement effects1,2,3,4,5,6,7. Such systems feature two-dimensional surface states whose electrodynamic properties are described not by the conventional Maxwell equations but rather by an attached axion field, originally proposed to describe interacting quarks8,9,10,11,12,13,14,15. It has been proposed that a topological insulator2 with a single Dirac cone interfaced with a superconductor can form the most elementary unit for performing fault-tolerant quantum computation14. Here we present an angle-resolved photoemission spectroscopy study that reveals the first observation of such a topological state of matter featuring a single surface Dirac cone realized in the naturally occurring Bi2Se3 class of materials. Our results, supported by our theoretical calculations, demonstrate that undoped Bi2Se3 can serve as the parent matrix compound for the long-sought topological device where in-plane carrier transport would have a purely quantum topological origin. Our study further suggests that the undoped compound reached via n-to-p doping should show topological transport phenomena even at room temperature.},
   author = {Y. Xia and D. Qian and D. Hsieh and L. Wray and A. Pal and H. Lin and A. Bansil and D. Grauer and Y. S. Hor and R. J. Cava and M. Z. Hasan},
   doi = {10.1038/nphys1274},
   issn = {1745-2481},
   issue = {6},
   journal = {Nature Physics},
   keywords = {Atomic,Classical and Continuum Physics,Complex Systems,Condensed Matter Physics,Mathematical and Computational Physics,Molecular,Optical and Plasma Physics,Physics,Theoretical,general},
   month = {5},
   pages = {398-402},
   publisher = {Nature Publishing Group},
   title = {Observation of a large-gap topological-insulator class with a single Dirac cone on the surface},
   volume = {5},
   url = {https://www.nature.com/articles/nphys1274},
   year = {2009}
}
@article{Pistore2023,
   abstract = {Excitation of Dirac plasmon polaritons (DPPs) in bi-dimensional materials have attracted considerable interest in recent years, both from perspectives of understanding their physics and exploring their transformative potential for nanophotonic devices, including ultra-sensitive plasmonic sensors, ultrafast saturable absorbers, modulators, and switches. Topological insulators (TIs) represent an ideal technological platform in this respect because they can support plasmon polaritons formed by Dirac carriers in the topological surface states. Tracing propagation of DPPs is a very challenging task, particularly at terahertz (THz) frequencies, where the DPP wavelength becomes over one order of magnitude shorter than the free space photon wavelength. Furthermore, severe attenuation hinders the comprehensive analysis of their characteristics. Here, the properties of DPPs in real TI-based devices are revealed. Bi2 Se3 rectangular antennas can efficiently confine the propagation of DPPs to a single dimension and, as a result, enhance the DPPs visibility despite the strong intrinsic attenuation. The plasmon dispersion and loss properties from plasmon profiles are experimentally determined, along the antennas, obtained using holographic near-field nano-imaging in a wide range of THz frequencies, from 2.05 to 4.3 THz. The detailed investigation of the unveiled DPP properties can guide the design of novel topological quantum devices exploiting their directional propagation.},
   author = {Valentino Pistore and Leonardo Viti and Chiara Schiattarella and Zhengtianye Wang and Stephanie Law and Oleg Mitrofanov and Miriam S. Vitiello},
   doi = {10.1002/SMLL.202308116},
   issn = {16136829},
   issue = {22},
   journal = {   Small      , Article e2308116. (2023)     (In press).  },
   keywords = {MBE,book chapters,conference proceedings,digital web resources,journal articles,large area topological insulators,near field,plasmon polaritons,research,theses,ucl,ucl library,ucl research},
   month = {12},
   pmid = {38152928},
   publisher = {Wiley},
   title = {Holographic Nano-Imaging of Terahertz Dirac Plasmon Polaritons Topological Insulator Antenna Resonators},
   volume = {20},
   url = {http://dx.doi.org/10.1002/smll.202308116},
   year = {2023}
}
@article{Locatelli2022,
   abstract = {Recently, the topological insulators (TIs) antimony telluride (Sb2Te3) and bismuth telluride (Bi2Te3) are attracting high interest for applications based on spin-charge interconversion mechanisms. Aiming to make a step toward the technology transfer, it is of major importance to achieve and investigate epitaxial quality-TIs on large area Si-based substrates. In view of that, we report here magnetotransport and angle-resolved photoemission spectroscopy (ARPES) studies on Sb2Te3 and Bi2Te3 thin films grown by metal organic chemical vapor deposition (MOCVD) on top of 4″ Si(111) substrates. Clear weak antilocalization (WAL) effects are observed in both TIs, proving the existence of quantum transport mechanism, and the data are successfully interpreted in the framework of the Hikami–Larkin–Nagaoka model. Further, by dedicated magnetotransport experiments, it has been confirmed that the investigated WAL originates from two-dimensional&nbsp;(2D) topological states. ARPES has been performed ex-situ, and in both TIs the gapless Dirac cones have been observed and attributed to the topological surface states. Combining the proofs of the existence of quantum 2D&nbsp;transport as deduced from the analysis of the magnetoconductance curve with the direct observation of the Dirac-like band structure revealed by the ARPES spectra, it is possible to unambiguously confirm the topological nature of our Sb2Te3 and Bi2Te3 thin films. The results obtained on thin films grown by MOCVD on 4’’ Si(111) substrate mark an important step towards the technology transfer of the topological insulators studied in this work.},
   author = {L. Locatelli and A. Kumar and P. Tsipas and A. Dimoulas and E. Longo and R. Mantovan},
   doi = {10.1038/s41598-022-07496-7},
   isbn = {0123456789},
   issn = {2045-2322},
   issue = {1},
   journal = {Scientific Reports},
   keywords = {Electronic devices,Information storage},
   month = {3},
   pages = {1-10},
   pmid = {35273194},
   publisher = {Nature Publishing Group},
   title = {Magnetotransport and ARPES studies of the topological insulators {Sb$_2$Te$_3$} and {Bi$_2$Te$_3$} grown by MOCVD on large-area Si substrates},
   volume = {12},
   url = {https://www.nature.com/articles/s41598-022-07496-7},
   year = {2022}
}
@article{Huang2021,
   abstract = {The magnetic susceptibility reveals a discontinuity at Néel temperature and a hysteresis loop with low coercive field was observed below Néel temperature. The magnetic susceptibility of zero field cool and field cool processes coincide at a temperature above the discontinuity, and they split at temperature blow the discontinuity. The magnetic susceptibility splitting is larger at lower external magnetic fields. No more magnetic susceptibility splitting was observed at a magnetic field above 7000 Oe which is consistent with the magnetic anisotropy energy. Our study supports that these magnetic susceptibility characteristics originate from an antiferromagnetic order accompanied by weak ferromagnetism.},
   author = {Shiu Ming Huang and Pin Cing Wang and Hao Lun Jian and Mitch M.C. Chou},
   doi = {10.1186/S11671-021-03637-5},
   issn = {1556276X},
   issue = {1},
   journal = {Nanoscale Research Letters},
   keywords = {Antiferromagnetism,Curie–Weiss law,Ferromagnetism topological material,Magnetic susceptibility},
   month = {12},
   pages = {1-6},
   publisher = {Springer},
   title = {The Magnetic Susceptibility Bifurcation in the Ni-Doped {Sb$_2$Te$_3$} Topological Insulator with Antiferromagnetic Order Accompanied by Weak Ferromagnetic Alignment},
   volume = {16},
   url = {https://link.springer.com/article/10.1186/s11671-021-03637-5},
   year = {2021}
}
@article{Huang2014,
   abstract = {Magnetotransport properties of a single crystal Sb2Te 3 topological insulator nanoflake with the thickness of 25 nm, synthesized via a vapor phase deposition method, are studied. The mobility and number of carriers are obtained through the Hall resistance measurement data. The magnetoresistance shows pronounced weak antilocalization effect. Temperature dependence of the phase coherence length confirms the 2D nature of the observed weak antilocalization effect. The fluctuations in the magnetoresistance are attributed to the combined contribution of the universal conductance fluctuation and the Shubnikov de Haas oscillations of the 2D electron gas. The Shubnikov de Haas oscillations reveal two well defined frequencies ascribed to states with spin-up and spin-down polarizations. The Rashba parameter and the energy gap between the two spin polarized subbands have been obtained and were equal to δ=0.75×10-11 eV m and ΔE=2.4 meV correspondingly. © 2014 Elsevier B.V.},
   author = {Yi Chi Huang and P. C. Lee and C. H. Chien and F. Y. Chiu and Y. Y. Chen and Sergey R. Harutyunyan},
   doi = {10.1016/J.PHYSB.2014.07.010},
   issn = {0921-4526},
   journal = {Physica B: Condensed Matter},
   keywords = {Magnetoresistance,Rashba effect,SdH oscillations,Topological insulator},
   month = {11},
   pages = {108-112},
   publisher = {North-Holland},
   title = {Magnetotransport properties of {Sb$_2$Te$_3$} nanoflake},
   volume = {452},
   year = {2014}
}
@article{Bergmann1984,
   abstract = {The resistance of two-dimensional electron systems such as thin disordered films shows deviations from Boltzmann theory, which are caused by quantum corrections and are called "weak localization". Theoretically weak localization is originated by the Langer-Neal graph in the Kubo formalism. In this review article the physics of weak localization is discussed. It represents an interference experiment with conduction electrons spl into pairs of waves interfering in the back-scattering direction. The intensity of the interference (integrated over the time) can be easily measured b the resistance of the film. A magnetic field introduces a magnetic phase shift in the electronic wave functionand suppresses the interference after a "flight" time proportional to 1/H. Therefore the application of a magnetic field allows a time-of-flight experiment with conduction electrons. Spin-orbit scattering rotates the spin of the electrons and yields an observable destructive interference. Magnetic impurities destroy the coherence of the phase. The experimental results as well as the theory is reviewed. The role of the spin-orbit scattering and the magnetic scattering are discussed. The measurements give selected information about the inelastic lifetime of the conduction electrons in disordered metals and raise new questions in solid state physics. Future applications of the method of weak localization are considered and expected. © 1984.},
   author = {Gerd Bergmann},
   doi = {10.1016/0370-1573(84)90103-0},
   issn = {0370-1573},
   issue = {1},
   journal = {Physics Reports},
   month = {5},
   pages = {1-58},
   publisher = {North-Holland},
   title = {Weak localization in thin films: a time-of-flight experiment with conduction electrons},
   volume = {107},
   year = {1984}
}
@article{Singh2018,
   abstract = {We investigate the dephasing mechanism in bulk insulating topological insulator thin films. The phase coherence length is extracted from magnetoresistance measurements at different temperatures. There is a crossover of the phase coherence length as a function of temperature signifying the role of more than one dephasing mechanism in the system. The dephasing rates have been studied systematically and explained.},
   author = {Sourabh Singh and R. K. Gopal and Jit Sarkar and Subhadip Roy and Chiranjib Mitra},
   doi = {10.1063/1.5032695},
   isbn = {9780735416482},
   issn = {15517616},
   issue = {1},
   journal = {AIP Conference Proceedings},
   month = {5},
   pages = {50040},
   publisher = {American Institute of Physics Inc.},
   title = {Evidence of charged puddles and induced dephasing in topological insulator thin films},
   volume = {1953},
   url = {/aip/acp/article/1953/1/050040/794453/Evidence-of-charged-puddles-and-induced-dephasing},
   year = {2018}
}
@article{Westlake1968,
   abstract = {The Bloch-Grüneisen relation is in excellent agreement with the experimentally determined ideal resistivity of vanadium at temperatures between 22 and 200°K. The characteristic temperature θD was found to be 320°K. At the higher temperatures of the investigation, the theoretical curve exhibited a positive deviation from the experimental curve. © 1968.},
   author = {D. G. Westlake and L. C.R. Alfred},
   doi = {10.1016/0022-3697(68)90043-7},
   issn = {0022-3697},
   issue = {11},
   journal = {Journal of Physics and Chemistry of Solids},
   month = {11},
   pages = {1931-1934},
   publisher = {Pergamon},
   title = {Determination of the debye characteristic temperature of vanadium from the Bloch-Grüneisen relation},
   volume = {29},
   year = {1968}
}
@article{Zhang2014,
   abstract = {Highly (00l)-textured antimony telluride films were fabricated using molecular beam epitaxy (MBE) on Si (111) substrate at 280 °C. X-ray diffraction analysis implying the samples have good crystalline quality, simultaneously, the grain sizes coarsening with increasing thickness. The results of Hall coefficient measurement demonstrated that the carrier concentration and mobility are strongly affected by grain boundaries and microcrystalline internal defects. It was found that the grain boundaries play a primary factor influencing the carrier concentration in thinner film. At room temperature, the results in a maximum mobility value of 305 cm 2/Vs for 121-nm-thick film, and the electrical conductivity increased from 425.7 S/cm to 1036 S/cm as the thickness varied from 28 nm to 121 nm. In the range of room temperature to 150 °C, the resistivity almost linearly increased with increasing temperature. This may be explained by low concentration of impurities or defects and shallow impurity band. For difference thickness films, temperature coefficients of resistivity are substantially equal, and the values are about 3 ∼ 4 μ Ω cm / K. © 2014 AIP Publishing LLC.},
   author = {Xiangpeng Zhang and Zhigang Zeng and Chao Shen and Ziqiang Zhang and Zhichong Wang and Cong Lin and Zhiyu Hu},
   doi = {10.1063/1.4861394/366787},
   issn = {00218979},
   issue = {2},
   journal = {Journal of Applied Physics},
   month = {1},
   pages = {24307},
   publisher = {AIP Publishing},
   title = {Investigation on the electrical transport properties of highly (00l)-textured {Sb$_2$Te$_3$} films deposited by molecular beam epitaxy},
   volume = {115},
   url = {/aip/jap/article/115/2/024307/366787/Investigation-on-the-electrical-transport},
   year = {2014}
}
@article{Lanius2016,
   abstract = {We have studied the growth process of the topological insulator (TI) Sb2Te3 on Si(111) by scanning tunneling microscopy. High quality thin films from more than 22 nm down to 1 nm in thickness have been deposited by molecular beam epitaxy. To determine the thickness and domain formation of the films, x-ray reflectivity and x-ray diffraction were utilized. In comparison to previous studies of the TI Bi2Te3, the growth mechanism of Sb2Te3 shows a similar transition from nucleation and growth in Sb–Te and Te–Te bilayers, respectively, to mound formation for thicker films. Atom probe tomography measurements reveal a intermixed interface between Sb2Te3 and Si(111) substrate. These findings can explain the high density of defects and domains.},
   author = {M. Lanius and J. Kampmeier and S. Kölling and G. Mussler and P. M. Koenraad and D. Grützmacher},
   doi = {10.1016/J.JCRYSGRO.2016.08.016},
   issn = {0022-0248},
   journal = {Journal of Crystal Growth},
   keywords = {A1. Atom probe tomography,A1. Crystal morphology,A3. Molecular beam epitaxy,B1. Antimonides,B1. Tellurides,B2. Topological insulator},
   month = {11},
   pages = {158-162},
   publisher = {North-Holland},
   title = {Topography and structure of ultrathin topological insulator {Sb$_2$Te$_3$} films on {Si(111)} grown by means of molecular beam epitaxy},
   volume = {453},
   year = {2016}
}
@article{Testardi1962,
   abstract = {The Seebeck coefficients, electrical and thermal conductivities and Hall coefficients of a number of p-type alloys from the (Bi,Sb)2Te3 pseudo-binary system have been measured in the temperature range 80-370°K. The results are found to be generally consistent with the assumptions of a many-valley valence band and charge carrier mobility limited by acoustical scattering, once corrections for the effects of degeneracy have been made using exact statistics. The possibilities of temperature and degeneracy-dependent band structures are discussed in relation to anomalies in the Hall and Seebeck coefficients. The Klemens-Drabble theory of thermal resistance due to point defect scattering (with a slightly modified form for the mass fluctuation parameter) is in good agreement with the experimental values for the lattice thermal conductivity of these alloys. The doping behavior of the alloys at room temperature also confirms the assumption of acoustical scattering of the charge carriers. © 1962.},
   author = {L. R. Testardi and J. N. Bierly and F. J. Donahoe},
   doi = {10.1016/0022-3697(62)90168-3},
   issn = {0022-3697},
   issue = {9},
   journal = {Journal of Physics and Chemistry of Solids},
   month = {9},
   pages = {1209-1217},
   publisher = {Pergamon},
   title = {Transport properties of p-type {Bi$_2$Te$_3$-Sb$_2$Te$_3$} alloys in the temperature range 80–370°K},
   volume = {23},
   year = {1962}
}
@article{Pinisetty2010,
   abstract = {In the present study, the thermal conductivity of superlattice bismuth-telluride (semiconductor)-antimony (semimetal) (Bi2Te3-Sb) nanostructures (nanowires and nanotubes) has been modeled using an incoherent particle model, approximating all the scattering to be diffuse and gray, and applying a Matthiessen-type simplification. The effect of varying the ratio of the superlattice nanowire segment lengths (L) of Sb and Bi2Te3 has also been studied assuming: (i) LSb =LBi2 Te3 ; (ii) LSb = 0.25 ×LBi2 Te3 ; (iii) LSb = 0.5 ×LBi2 Te3 ; (iv) LSb = 2.0 ×LBi2 Te3 ; and (v) LSb = 4.0 ×LBi2 Te3 . It is shown that thermal conductivity of the superlattice nanowires reduces either with a reduction of segment lengths (LSb and LBi2 Te3) or with a reduction of nanowire diameter. Specifically, the thermal conductivity is lower than 2 W m-1 K-1 (the bulk value for Bi2Te3), even when the nanowire diameters (10 nm) are 10 times larger than the mean free path (1 nm) of Bi2Te3, provided the individual segment lengths (LSb and LBi2 Te3) are lower than the mean free path limit. The thermal conductivity of either superlattice nanowires or superlattice nanotubes was also observed to decrease, as the segment length of semimetal (Sb) is lowered relative to the segment length of semiconductor (Bi2Te3). In the case of superlattice nanotubes, a reduction in wall thickness caused a corresponding reduction in thermal conductivity as well. For example, with a fixed outer diameter value of 5 nm, the thermal conductivity of the nanotubes can be lowered by ∼33% by decreasing the tube wall thickness from 0.75 to 0.1 nm. Our predictions also suggest that for a given value of the segment lengths of LSb and LBi2 Te3, nanotubes exhibit a lower thermal conductivity than nanowires. This therefore suggests that nanotubes of superlattice structures of Sb and Bi2Te3 should exhibit a higher thermoelectric figure of merit (ZT) than nanowires under corresponding conditions. © 2009 Acta Materialia Inc.},
   author = {D. Pinisetty and R. V. Devireddy},
   doi = {10.1016/J.ACTAMAT.2009.09.035},
   issn = {1359-6454},
   issue = {2},
   journal = {Acta Materialia},
   keywords = {Boltzmann transport equation,Matthiessen model,Nanotubes,Nanowires,Thermoelectric figure of merit},
   month = {1},
   pages = {570-576},
   publisher = {Pergamon},
   title = {Thermal conductivity of semiconductor (bismuth–telluride)–semimetal (antimony) superlattice nanostructures},
   volume = {58},
   year = {2010}
}
@article{Chiu2013,
   abstract = {We have studied the carrier transport in two topological insulator (TI) Bi2Te3 microflakes between 0.3 and 10 K and under applied backgate voltages (VBG). Logarithmic temperature dependent resistance corrections due to the two-dimensional electron-electron interaction effect in the presence of weak disorder were observed. The extracted Coulomb screening parameter is negative, which is in accord with the situation of strong spin-orbit scattering as is inherited in the TI materials. In particular, positive magnetoresistances (MRs) in the two-dimensional weak-antilocalization (WAL) effect were measured in low magnetic fields, which can be satisfactorily described by a multichannel-conduction model. Both at low temperatures of T<1 K and under high positive VBG, signatures of the presence of two coherent conduction channels were observed, as indicated by an increase by a factor of ≈2 in the prefactor which characterizes the WAL MR magnitude. Our results are discussed in terms of the (likely) existence of the Dirac fermion surface states, in addition to the bulk states, in the three-dimensional TI Bi2Te3 material. © 2013 American Physical Society.},
   author = {Shao Pin Chiu and Juhn Jong Lin},
   doi = {10.1103/PHYSREVB.87.035122},
   issn = {10980121},
   issue = {3},
   journal = {Physical Review B - Condensed Matter and Materials Physics},
   month = {1},
   title = {Weak antilocalization in topological insulator {Bi$_2$Te$_3$} microflakes},
   volume = {87},
   year = {2013}
}
@article{Salehi2015,
   abstract = {Although over the past number of years there have been many advances in the materials aspects of topological insulators (TIs), one of the ongoing challenges with these materials is the protection of them against aging. In particular, the recent development of low-carrier-density bulk-insulating Bi2Se3 thin films and their sensitivity to air demands reliable capping layers to stabilize their electronic properties. Here, we study the stability of the low-carrier-density Bi2Se3 thin films in air with and without various capping layers using DC and THz probes. Without any capping layers, the carrier density increases by ∼150% over a week and by ∼280% over 9 months. In situ-deposited Se and ex situ-deposited poly(methyl methacrylate) suppress the aging effect to ∼27% and ∼88%, respectively, over 9 months. The combination of effective capping layers and low-carrier-density TI films will open up new opportunities in topological insulators.},
   author = {Maryam Salehi and Matthew Brahlek and Nikesh Koirala and Jisoo Moon and Liang Wu and N. P. Armitage and Seongshik Oh},
   issn = {2166532X},
   issue = {9},
   journal = {APL Materials},
   month = {9},
   pages = {91101},
   publisher = {American Institute of Physics Inc.},
   title = {Stability of low-carrier-density topological-insulator {Bi$_2$Se$_3$} thin films and effect of capping layers},
   volume = {3},
   url = {/aip/apm/article/3/9/091101/120576/Stability-of-low-carrier-density-topological},
   year = {2015}
}
@article{Wu2019,
   abstract = {The quantum anomalous Hall effect (QAHE) observed in magnetically doped topological insulators is not only fundamentally interesting but also has great potential applications such as quantum computation. To experimentally realize the QAHE, the Fermi level (E F ) needs to be stabilized in the tiny surface-state gap. However, for topological insulators, even a very short time exposure to the atmosphere can induce a large E F shift. In this work, magnetic topological insulator Cr 0.27 (Bi 0.43 Sb 0.63 ) 1.73 Te 3 (CBST) thin-films are successfully prepared via magnetron sputtering, which is a more universal, efficient, and affordable method for application. Then, the evolution of the E F position has been investigated as a function of the exposure time in the air through gate-dependent transport measurements. This study reveals that the E F position can be stabilized by in situ Al passivation with carrier doping significantly reduced, and the oxidations of Bi and Te atoms can also be suppressed. The availability of wide compositions for magnetron sputtering as well as the E F position stability of the in situ Al passivation may be a key for further investigations of the topological insulator toward the achievement of the QAHE in the sputtered CBST thin-film systems.},
   author = {Yu Wu and Qixun Guo and Qi Zheng and Xiulan Xu and Tao Liu and Yang Liu and Yu Yan and Dongwei Wang and Shibing Long and Lijin Wang and Shanwu Yang and Jiao Teng and Shixuan Du and Guanghua Yu},
   doi = {10.1021/ACS.JPCC.8B09661},
   issn = {19327455},
   issue = {6},
   journal = {Journal of Physical Chemistry C},
   month = {2},
   pages = {3823-3828},
   publisher = {American Chemical Society},
   title = {Stabilizing the Fermi Level of Cr-Doped Magnetic Topological Insulators by Al Passivation},
   volume = {123},
   url = {https://pubs.acs.org/doi/full/10.1021/acs.jpcc.8b09661},
   year = {2019}
}
@article{Dumpich1991,
   abstract = {Magnetoresistance measurements as well as transmission-electron-microscopy investigations are carried out for thin gold films of varied topography. For gold films with percolative structure we find an anomalous temperature dependence of the phase coherence length L(T), if the percolation correlation length p>L(T). This can be understood in terms of anomalous diffusion. Moreover, comparing these results with L(T) for nonpercolating (homogeneous) gold films yields critical exponents of two-dimensional percolation, quantitatively. © 1991 The American Physical Society.},
   author = {G. Dumpich and A. Carl},
   doi = {10.1103/PhysRevB.43.12074},
   issn = {01631829},
   issue = {14},
   journal = {Physical Review B},
   pages = {12074-12077},
   title = {Anomalous temperature dependence of the phase-coherence length for inhomogeneous gold films},
   volume = {43},
   year = {1991}
}
@article{Emziane2000,
   abstract = {α-In2Se3 thin films were prepared by sequential thermal evaporation of indium and selenium layers followed by annealing in flowing argon. The structure and the phase of the films were confirmed by X-ray diffraction (XRD), scanning electron microscope (SEM), microprobe analysis, optical absorption, Raman measurements and room temperature conductivity measurements. The influence of the preparation on the formation of different In2Se3-modifications is discussed. © 2000 Published by Elsevier Science S.A.},
   author = {M. Emziane and S. Marsillac and J. C. Bernéde},
   doi = {10.1016/S0254-0584(99)00145-5},
   issn = {0254-0584},
   issue = {1},
   journal = {Materials Chemistry and Physics},
   keywords = {Argon flux,Thin flms,α-In2Se3},
   month = {1},
   pages = {84-87},
   publisher = {Elsevier},
   title = {Preparation of highly oriented {$\alpha$}-{In$_2$Se$_3$} thin films by a simple technique},
   volume = {62},
   year = {2000}
}
@article{Lin2018,
   abstract = {To preserve the high quality topological surface state after air exposure without degradation, it is crucial to identify an effective capping layer. In this study, we report an effective capping layer obtained by crystallizing Se. Upon extended exposure to ultrahigh vacuum or humid air, we show by using x-ray photoemission spectroscopy that the stability and resistance to oxidation of crystalline Se capping layers are superior to those of the amorphous Se capping layer, which has been commonly used by current communities. Furthermore, time-dependent Hall measurements showed that crystalline Se capping layers had a much stronger ability to sustain the intrinsic transport properties of Bi2Se3.},
   author = {H. Y. Lin and C. K. Cheng and K. H.M. Chen and C. C. Tseng and S. W. Huang and M. T. Chang and S. C. Tseng and M. Hong and J. Kwo},
   doi = {10.1063/1.5029706/121726},
   issn = {2166532X},
   issue = {6},
   journal = {APL Materials},
   month = {6},
   publisher = {American Institute of Physics Inc.},
   title = {A new stable, crystalline capping material for topological insulators},
   volume = {6},
   url = {/aip/apm/article/6/6/066108/121726/A-new-stable-crystalline-capping-material-for},
   year = {2018}
}
@article{Friedensen2017,
   abstract = {Focused ion beam milling allows manipulation of the shape and size of nanostructures to create geometries potentially useful for opto-electronics, thermoelectrics, and quantum computing. We focus on using the ion beam to control the thickness of Bi2Se3 and to create nanowires from larger structures. Changes in the material structure of Bi2Se3 nanomaterials that have been milled using a focused ion beam are presented. In order to characterize the effects of ion beam processing on the samples, we use a variety of techniques including analytical transmission electron microscopy and atomic force microscopy. The results show that while part of the material remains intact after shaping, amorphous regions form where the beam has been used to thin the sample. For wires created by thinning the material down to the substrate, the sidewalls of the wires appear intact based on diffraction images from samples cut at an angle, but thin crystalline regions remain at the wire edges. Even with the resulting defects and limitations when thinning, focused ion beam milling can be used to fabricate custom geometries of Bi2Se3 nanostructures.},
   author = {Sarah Friedensen and Jerome T. Mlack and Marija Drndić},
   doi = {10.1038/s41598-017-13863-6},
   issn = {2045-2322},
   issue = {1},
   journal = {Scientific Reports 2017 7:1},
   keywords = {Structural properties,Synthesis and processing},
   month = {10},
   pages = {1-7},
   pmid = {29044163},
   publisher = {Nature Publishing Group},
   title = {Materials analysis and focused ion beam nanofabrication of topological insulator {Bi$_2$Se$_3$}},
   volume = {7},
   url = {https://www.nature.com/articles/s41598-017-13863-6},
   year = {2017}
}
@article{Knox2024,
   abstract = {We have performed an investigation into the optical conductivity and magnetotransport properties of top-gated devices patterned on the topological insulator Bi2Se3 in order to determine the relative effects of the different carrier species that exist within these novel materials. We find that the topologically protected surfaces within our samples are partially screened from the action of the gate by trivial band-bending states formed at the top surface of the topological insulator. Despite this, the mobility of the topological surface carriers is significantly affected by the application of an external gate bias. Additionally, we find that the optical conductivity response is dominated by the topologically protected surface states, and that the optical conductivity is particularly sensitive to the scattering caused by the topological surfaces coupling to trivial states, arising from the bulk or band-bending induced surface states. These results will have interesting applications to the design of future plasmonic devices that incorporate topological materials.},
   author = {Craig S. Knox and Matthew T. Vaughan and Nathan R. Fox and Ahmet Yagmur and Satoshi Sasaki and John E. Cunningham and Edmund H. Linfield and Alexander G. Davies and Joshua R. Freeman},
   doi = {10.1515/NANOPH-2023-0690/DOWNLOADASSET/SUPPL/J_NANOPH-2023-0690_SUPPL_001.DOCX},
   issn = {21928614},
   issue = {10},
   journal = {Nanophotonics},
   keywords = {THz time domain spectroscopy,quantum transport,topological insulators},
   month = {4},
   pages = {1843-1850},
   publisher = {Walter de Gruyter GmbH},
   title = {Optical conductivity of a {Bi$_2$Se$_3$} topological insulator with a {THz} transparent top gate},
   volume = {13},
   url = {https://www.degruyter.com/document/doi/10.1515/nanoph-2023-0690/html?lang=en&srsltid=AfmBOorfz5s9RJdZI_uJwbL4No4PZ3Ld3cO7e49os-RgNCzNiJI8HEbG},
   year = {2024}
}
@article{Shi2016,
   abstract = {Few layer phosphorene (FLP) devices are extensively studied due to their unique electronic properties and potential applications on nano-electronics. Here we present magnetotransport studies which reveal electronCelectron interactions as the dominant scattering mechanism in hexagonal boron nitride-encapsulated FLP devices. From weak localization measurements, we estimate the electron dephasing length to be 30 to 100 nmat low temperatures, which exhibits a strong dependence on carrier density n and a power-law dependence on temperature (∼T-0.4). These results establish that the dominant scattering mechanism in FLP is electronCelectron interactions.},
   author = {Yanmeng Shi and Nathaniel Gillgren and Timothy Espiritu and Son Tran and Jiawei Yang and Kenji Watanabe and Takahashi Taniguchi and Chun Ning Lau},
   doi = {10.1088/2053-1583/3/3/034003},
   issn = {2053-1583},
   issue = {3},
   journal = {2D Materials},
   keywords = {2D materials,Electron-electron interactions,Phosphorene,Weak localization},
   month = {8},
   pages = {034003},
   publisher = {IOP Publishing},
   title = {Weak localization and electron–electron interactions in few layer black phosphorus devices},
   volume = {3},
   url = {https://iopscience.iop.org/article/10.1088/2053-1583/3/3/034003 https://iopscience.iop.org/article/10.1088/2053-1583/3/3/034003/meta},
   year = {2016}
}
@article{Altshuler1982,
   abstract = {The effect of electron-electron collisions with small energy transfers on the quantum electron localisation has been studied. It is shown that in one and two dimensions such collisions determine the temperature dependence of the conductivity. In three dimensions the contribution of processes with small energy transfers is less than that of the usual electron-electron collisions, in which the energy transfer is of the order of the temperature T. The criterion for the quasiparticle description of electrons in metals in different dimensions is discussed. It is shown that for d>or=2 this description is valid, while for d=1 it is not correct. The effect of noise in the external circuit on quantum corrections to the conductivity is studied.},
   author = {B. L. Altshuler and A. G. Aronov and D. E. Khmelnitsky},
   doi = {10.1088/0022-3719/15/36/018},
   issn = {0368-3516},
   issue = {36},
   journal = {Journal of Physics C: Solid State Physics},
   pages = {7367-7386},
   title = {Effects of electron-electron collisions with small energy transfers on quantum localisation},
   volume = {15},
   url = {https://ui.adsabs.harvard.edu/abs/1982JPhC...15.7367A/abstract},
   year = {1982}
}
@article{Ando1982,
   abstract = {The electronic properties of inversion and accumulation layers at semiconductor-insulator interfaces and of other systems that exhibit two-dimensional or quasi-two-dimensional behavior, such as electrons in semiconductor heterojunctions and superlattices and on liquid helium, are reviewed. Energy levels, transport properties, and optical properties are considered in some detail, especially for electrons at the (100) silicon-silicon dioxide interface. Other systems are discussed more briefly. © 1982 The American Physical Society.},
   author = {Tsuneya Ando and Alan B. Fowler and Frank Stern},
   doi = {10.1103/RevModPhys.54.437},
   issn = {00346861},
   issue = {2},
   journal = {Reviews of Modern Physics},
   pages = {437-672},
   title = {Electronic properties of two-dimensional systems},
   volume = {54},
   year = {1982}
}
@article{Lin1987,
   abstract = {We have conducted extensive measurements of the low-temperature magnetoresistance of thin Au-Pd films and very-small-diameter Au-Pd wires. These results have been used to determine the importance of localization and electron-electron interaction effects in these systems. The magnetoresistance in the small magnetic fields employed in this work (<10 kG) appears to be due predominantly to localization. However, both localization and interactions contribute to the variation of the resistance with temperature in zero field, with interactions generally being dominant. From the measurements as a function of magnetic field, we have determined the inelastic scattering time, i, the magnetic impurity scattering time, s, and have placed an upper limit on the spin-orbit scattering time, so. We find that s is essentially the same for the films and wires, as expected since this is predicted to be a material (i.e., bulk) property which should be independent of dimensionality. The upper limits on so in one and two dimensions are also consistent. In contrast i depends on the dimensionality of the sample, and has distinctly different temperature dependences in the two cases. In the films it appears to be due to electron-electron scattering in the presence of disorder in the two-dimensional limit, while in the wires it is due to the one-dimensional version of this scattering mechanism. © 1987 The American Physical Society.},
   author = {J. J. Lin and N. Giordano},
   doi = {10.1103/PhysRevB.35.545},
   issn = {01631829},
   issue = {2},
   journal = {Physical Review B},
   pages = {545-556},
   title = {Localization and electron-electron interaction effects in thin Au-Pd films and wires},
   volume = {35},
   year = {1987}
}
@article{Kaveh1984,
   abstract = {Recent developments are reviewed in the theory and measurement of electron-electron scattering and its contribution to the electrical and thermal resistivities for different types of conducting materials, such as extremely impure metals, one-dimensional and two-dimensional conductors, the simple metals, transition metals, semimetals, organic conductors and the A15 compounds. The discussion includes the following topics: quantum corrections to the Fermi-liquid theory of electron-electron scattering (EES) due to static disorder, the effect of the dimensionality of the system on EES, the measurement and the calculation of the EES contribution to the resistivity of metals, the observed sample dependence of EES for the simple metals, the effect of EES on electron-surface scattering for thin wires, the contribution of EES to the anomalous surface impedance and to the optical relaxation time and the effect of a magnetic field on EES. Comparison is made between theory and recent experimental data for each of these topics. © Taylor & Francis Group, LLC.},
   author = {Moshe Kaveh and Nathan Wiser},
   doi = {10.1080/00018738400101671},
   issn = {14606976},
   issue = {4},
   journal = {Advances in Physics},
   month = {1},
   pages = {257-372},
   publisher = {Taylor \& Francis Group},
   title = {Electron-electron scattering in conducting materials},
   volume = {33},
   url = {https://www.tandfonline.com/doi/abs/10.1080/00018738400101671},
   year = {1984}
}
@article{Altshuler1980,
   abstract = {Interaction effects in disordered Fermi systems are considered in the metallic regime. In two dimensions, logarithmic corrections are obtained for conductivity, density of states, specific heat, and Hall constant. These results are compared with a recent theory of localization as well as some experiments. © 1980 The American Physical Society.},
   author = {B. L. Altshuler and A. G. Aronov and P. A. Lee},
   doi = {10.1103/PhysRevLett.44.1288},
   issn = {00319007},
   issue = {19},
   journal = {Physical Review Letters},
   pages = {1288-1291},
   title = {Interaction Effects in Disordered Fermi Systems in Two Dimensions},
   volume = {44},
   year = {1980}
}
@article{Takagaki2012,
   abstract = {We investigate the low-temperature transport properties in Cu xBi 2-xSe 3 films prepared by a hot-wall-epitaxy growth of Bi 2Se 3 layers on Cu-deposited substrates. We observe a positive magnetoresistance due to the weak antilocalization effect and a classical magnetoresistance that exhibits a power-law dependence on the magnetic field. The resistance increases logarithmically with lowering temperature regardless of the strength of the magnetic field. The electron-electron interaction effect is thus evidenced to be strong. While the magnitude of the weak antilocalization effect is in reasonable agreement with theory, the correction to the conductivity due to the electron-electron interaction effect is unaccountably larger than the theoretical prediction. The discrepancy may indicate that the contribution from the bulk state is as large as that from the surface states, at least, for the interaction effect. © 2012 American Physical Society.},
   author = {Y. Takagaki and B. Jenichen and U. Jahn and M. Ramsteiner and K. J. Friedland},
   doi = {10.1103/PHYSREVB.85.115314/FIGURES/4/MEDIUM},
   issn = {10980121},
   issue = {11},
   journal = {Physical Review B - Condensed Matter and Materials Physics},
   month = {3},
   pages = {115314},
   publisher = {American Physical Society},
   title = {Weak antilocalization and electron-electron interaction effects in Cu-doped Bi 2Se 3 films},
   volume = {85},
   url = {https://journals.aps.org/prb/abstract/10.1103/PhysRevB.85.115314},
   year = {2012}
}
@article{Abrahams1981,
   abstract = {A calculation of the electron quasiparticle lifetime in a disordered metal due to electron-electron scattering is given. The calculation takes account of the diffusive nature of electron motion which leads to enhancement of the diagonal exchange term of the electron self-energy. The lifetime, as a function of temperature, behaves as T-d2 where d is the dimensionality, in contrast to the T-2 behavior of ordinary Fermi-liquid theory. At d=2, a logarithmic singularity occurs which leads to (TlnT)-1 behavior of the lifetime and a failure of the quasiparticle picture near the Fermi surface. The calculated lifetime agrees in temperature, Fermi energy, and elastic mean-free-path dependence with recent experiments on silicon inversion layers. © 1981 The American Physical Society.},
   author = {Elihu Abrahams and P. W. Anderson and P. A. Lee and T. V. Ramakrishnan},
   doi = {10.1103/PhysRevB.24.6783},
   issn = {01631829},
   issue = {12},
   journal = {Physical Review B},
   month = {12},
   pages = {6783},
   publisher = {American Physical Society},
   title = {Quasiparticle lifetime in disordered two-dimensional metals},
   volume = {24},
   url = {https://journals.aps.org/prb/abstract/10.1103/PhysRevB.24.6783},
   year = {1981}
}
@article{Gerami2024,
   author = {Hamidreza Gerami and Jean-Marc Cote and Antonio Jesús Santos and Nicolas Martin},
   doi = {10.1016/J.SURFIN.2024.105113},
   issn = {2468-0230},
   journal = {Surfaces and Interfaces},
   month = {11},
   pages = {105113},
   publisher = {Elsevier},
   title = {Low temperature dependence of electrical resistivity in obliquely sputter-deposited transition metal thin films},
   volume = {54},
   url = {https://linkinghub.elsevier.com/retrieve/pii/S2468023024012690},
   year = {2024}
}
@article{VanDendries1981,
   abstract = {Resistance measurements have been made on low-resistivity thin Cu films (50-500) between 1 and 20 K. A logarithmic temperature dependence of the resistance is observed. For a resistance per square of R<20 Ω/□, good agreement is obtained with the localization theory. The amplitude of the resistance variation and its large magnetic-field dependence exclude possible Coulomb-interaction effects predicted by Altshuler et al. as the main source of the observed behavior. © 1981 The American Physical Society.},
   author = {L. Van Den dries and C. Van Haesendonck and Y. Bruynseraede and G. Deutscher},
   doi = {10.1103/PhysRevLett.46.565},
   issn = {00319007},
   issue = {8},
   journal = {Physical Review Letters},
   month = {2},
   pages = {565},
   publisher = {American Physical Society},
   title = {Two-Dimensional Localization in Thin Copper Films},
   volume = {46},
   url = {https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.46.565},
   year = {1981}
}
@article{Dumoulin1984,
   abstract = {We investigate the temperature and magnetic field dependence of the resistance R of thin Pd and PdHx films. We show that the logarithmic behaviour R(T) ≈ A ln T is dominated in Pd by the interaction effect. Loading progressively with hydrogen shows first no change in A and then a decrease followed by a sign reversal when superconducting fluctuations prevail. The application of a magnetic field restores then a positive and large value of A. These data are analyzed within recent theories. © 1984.},
   author = {L. Dumoulin and H. Raffy and P. Nedellec and D. S. MacLachlan and J. P. Burger},
   doi = {10.1016/0038-1098(84)90240-0},
   issn = {0038-1098},
   issue = {2},
   journal = {Solid State Communications},
   month = {7},
   pages = {85-88},
   publisher = {Pergamon},
   title = {Weak localization and electron-electron interactions in thin {Pd and PdHx} films},
   volume = {51},
   year = {1984}
}
@article{Wu2015-2,
   abstract = {The dielectric constant or relative permittivity (εr) of a dielectric material, which describes how the net electric field in the medium is reduced with respect to the external field, is a parameter of critical importance for charging and screening in electronic devices. Such a fundamental material property is intimately related to not only the polarizability of individual atoms but also the specific atomic arrangement in the crystal lattice. In this Letter, we present both experimental and theoretical investigations on the dielectric constant of few-layer In2Se3 nanoflakes grown on mica substrates by van der Waals epitaxy. A nondestructive microwave impedance microscope is employed to simultaneously quantify the number of layers and local electrical properties. The measured εr increases monotonically as a function of the thickness and saturates to the bulk value at around 6-8 quintuple layers. The same trend of layer-dependent dielectric constant is also revealed by first-principles calculations. Our results of the dielectric response, being ubiquitously applicable to layered 2D semiconductors, are expected to be significant for this vibrant research field.},
   author = {Di Wu and Alexander J. Pak and Yingnan Liu and Yu Zhou and Xiaoyu Wu and Yihan Zhu and Min Lin and Yu Han and Yuan Ren and Hailin Peng and Yu Hao Tsai and Gyeong S. Hwang and Keji Lai},
   doi = {10.1021/ACS.NANOLETT.5B03575},
   issn = {15306992},
   issue = {12},
   journal = {Nano Letters},
   keywords = {In2Se3 nanoflakes,Microwave impedance microscopy,first-principles calculations,layer-dependent dielectric constant,layered materials,polarization},
   month = {12},
   pages = {8136-8140},
   publisher = {American Chemical Society},
   title = {Thickness-Dependent Dielectric Constant of Few-Layer {In$_2$Se$_3$} Nanoflakes},
   volume = {15},
   url = {https://pubs.acs.org/doi/full/10.1021/acs.nanolett.5b03575},
   year = {2015}
}
@article{Kolodzey2000,
   abstract = {Leakage currents and dielectric breakdown were studied in MIS capacitors of metal-aluminum oxide-silicon. The aluminum oxide was produced by thermally oxidizing AlN at 800-1100 C under dry O 2 conditions. The AlN films were deposited by RF magnetron sputtering on p-type Si (100) sub-strates. Thermal oxidation produced Al 2 O 3 with a thickness and structure that depended on the process time and temperature. The MIS capacitors exhibited the charge regimes of accumulation, depletion, and inversion on the Si semiconductor surface. The best electrical properties were obtained when all of the AlN was fully oxidized to Al 2 O 3 with no residual AlN. The MIS flatband voltage was near 0 V, the net oxide trapped charge density, ox , was less than 10 11 cm 2 , and the interface trap density, , was less than 10 11 cm 2 eV 1. At an oxide electric field of 0.3 MV/cm, the leakage current density was less than 10 7 A cm 2 , with a resistivity greater than 10 12-cm. The critical field for dielectric breakdown ranged from 4 to 5 MV/cm. The temperature dependence of the current versus electric field indicated that the conduction mechanism was Frenkel-Poole emission, which has the interesting property that higher temperatures reduce the current. This may be important for the reliability of circuits operating under extreme conditions. The dielectric constant ranged from 3 to 9. The excellent electronic quality of aluminum oxide may be attractive for field effect transistor applications.},
   author = {James Kolodzey and Senior Member and Enam Ahmed Chowdhury and Thomas N Adam and Guohua Qui and I Rau and Johnson Olufemi Olowolafe and John S Suehle and Yuan Chen},
   issue = {1},
   journal = {IEEE TRANSACTIONS ON ELECTRON DEVICES},
   keywords = {Index Terms-Dielectric breakdown,MIS capacitors,MOS ca-pacitors,semiconductor-insulator interfaces},
   pages = {121},
   title = {Electrical Conduction and Dielectric Breakdown in Aluminum Oxide Insulators on Silicon},
   volume = {47},
   year = {2000}
}
@article{Politano2017,
   abstract = {We have investigated the electronic response of single crystals of indium selenide by means of angle-resolved photoemission spectroscopy, electron energy loss spectroscopy and density functional theory. The loss spectrum of indium selenide shows the direct free exciton at ~1.3 eV and several other peaks, which do not exhibit dispersion with the momentum. The joint analysis of the experimental band structure and the density of states indicates that spectral features in the loss function are strictly related to single-particle transitions. These excitations cannot be considered as fully coherent plasmons and they are damped even in the optical limit, i.e. for small momenta. The comparison of the calculated symmetry-projected density of states with electron energy loss spectra enables the assignment of the spectral features to transitions between specific electronic states. Furthermore, the effects of ambient gases on the band structure and on the loss function have been probed.},
   author = {A. Politano and D. Campi and M. Cattelan and I. Ben Amara and S. Jaziri and A. Mazzotti and A. Barinov and B. Gürbulak and S. Duman and S. Agnoli and L. S. Caputi and G. Granozzi and A. Cupolillo},
   doi = {10.1038/s41598-017-03186-x},
   issn = {2045-2322},
   issue = {1},
   journal = {Scientific Reports 2017 7:1},
   keywords = {Electronic devices,Electronic properties and devices},
   month = {6},
   pages = {1-11},
   pmid = {28611385},
   publisher = {Nature Publishing Group},
   title = {Indium selenide: an insight into electronic band structure and surface excitations},
   volume = {7},
   url = {https://www.nature.com/articles/s41598-017-03186-x},
   year = {2017}
}
@article{Fang2020,
   abstract = {Dielectric properties and their evolutions are fundamental to reveal the optical responses of topological insulators and to guide the design of related devices. Here, we systematically investigate the layer-dependent dielectric permittivity of Bi2Se3 over an ultra-broad spectral range (0.73–6.43 eV) by combining the spectroscopic ellipsometry, energy-loss function (ELF), critical point (CP) analysis, and density function theory. Results demonstrate that the epsilon-near-zero point of the real permittivity and the ELF peak exhibit blue shifts, indicating the resonance frequencies of surface plasmon modes move towards the higher energy, due to the enhanced hybridization between the opposite surfaces. The joint density of states dominates the layer-dependent increase in imaginary permittivity as the thickness increases. We also find that the CP transition positions in band structures are layer-independent, and the CP center energies exhibit red shifts resulted by the reduced surface state gap with the thickness increasing.},
   author = {Mingsheng Fang and Zhengyu Wang and Honggang Gu and Mingyu Tong and Baokun Song and Xiangnan Xie and Tong Zhou and Xiuguo Chen and Hao Jiang and Tian Jiang and Shiyuan Liu},
   doi = {10.1016/J.APSUSC.2019.144822},
   issn = {0169-4332},
   journal = {Applied Surface Science},
   keywords = {Bi2Se3 thin films,Hybridization,Joint density of states,Layer-dependent dielectric permittivity,Spectroscopic ellipsometry},
   month = {4},
   pages = {144822},
   publisher = {North-Holland},
   title = {Layer-dependent dielectric permittivity of topological insulator {Bi$_2$Se$_3$} thin films},
   volume = {509},
   year = {2020}
}
@article{Kambas1978,
   abstract = {Far-infrared reflectance measurements have been made on cleaved surfaces of the ordered and disordered forms of α-In2Se3 at room temperature, between 10 cm-1 and 400 cm-1 for Ē ⊥ c̄. The results were analyzed by the methods of Kramers-Krönig and Lorentz. The spectra of the disordered form show an extremely high reflectivity in the low frequency range. The influence of annealing on the ordering of crystal lattice was examined. Despite the complex structure of this compound both spectra of ordered and disordered form are very simple. © 1978.},
   author = {K. Kambas and J. Spyridelis},
   doi = {10.1016/0025-5408(78)90085-5},
   issn = {0025-5408},
   issue = {7},
   journal = {Materials Research Bulletin},
   month = {7},
   pages = {653-660},
   publisher = {Pergamon},
   title = {Far infrared optical study of {$\alpha$-In$_2$Se$_3$} compound},
   volume = {13},
   year = {1978}
}
@article{Uren1981,
   abstract = {Discusses the effect of a magnetic field on the weak localisation of a two-dimensional electron gas. It is shown that due to quantum corrections the electron-electron relaxation time tau ee varies with electron temperature T and tau ee-1=A1T+A 2T2, in the temperature range 3K-0.1K. This short tau ee causes a rapid transition between states which are weakly localised and so reduces the logarithmic correction to the conductance. Negative magnetoresistance measurements are reported for (100) silicon MOSFETs in the temperature range 0.1-4K.},
   author = {M. J. Uren and R. A. Davies and M. Kaveh and M. Pepper},
   doi = {10.1088/0022-3719/14/13/003},
   issn = {0022-3719},
   issue = {13},
   journal = {Journal of Physics C: Solid State Physics},
   month = {5},
   pages = {L395},
   publisher = {IOP Publishing},
   title = {Magnetic delocalisation of a two-dimensional electron gas and the quantum law of electron-electron scattering},
   volume = {14},
   url = {https://iopscience.iop.org/article/10.1088/0022-3719/14/13/003 https://iopscience.iop.org/article/10.1088/0022-3719/14/13/003/meta},
   year = {1981}
}
@article{Davies1983,
   abstract = {The authors present the results of an investigation of the rate of electron-electron scattering in the two-dimensional electron gas of the Si inversion layer. The electron-electron scattering rate was extracted by analysis of the negative magnetoresistance in the regime of weak localisation when kFl>1, where kF is the Fermi wavevector and l is the mean free path for elastic scattering. The results showed that over a wide range of kFl, carrier concentration and electron mobility the scattering rate was given by two processes which were additive. The first was the normal T2 (Landau-Baber) law and the second was the T law expected when the effects of disorder are considered. There was no evidence for the recently proposed T ln T law.},
   author = {R. A. Davies and M. Pepper},
   doi = {10.1088/0022-3719/16/12/003},
   issn = {0022-3719},
   issue = {12},
   journal = {Journal of Physics C: Solid State Physics},
   month = {4},
   pages = {L353},
   publisher = {IOP Publishing},
   title = {Electron-electron scattering in silicon inversion layers},
   volume = {16},
   url = {https://iopscience.iop.org/article/10.1088/0022-3719/16/12/003 https://iopscience.iop.org/article/10.1088/0022-3719/16/12/003/meta},
   year = {1983}
}
@article{Kong2010,
   abstract = {A topological insulator (TI) represents an unconventional quantum phase of matter with insulating bulk band gap and metallic surface states. Recent theoretical calculations and photoemission spectroscopy measurements show that group V-VI materials Bi2Se3, Bi2Te3, and Sb2Te3 are TIs with a single Dirac cone on the surface. These materials have anisotropic, layered structures, in which five atomic layers are covalently bonded to form a quintuple layer, and quintuple layers interact weakly through van der Waals interaction to form the crystal. A few quintuple layers of these materials are predicted to exhibit interesting surface properties. Different from our previous nanoribbon study, here we report the synthesis and characterizations of ultrathin Bi2Te3 and Bi2Se3 nanoplates with thickness down to 3 nm (3 quintuple layers), via catalyst-free vapor-solid (VS) growth mechanism. Optical images reveal thickness-dependent color and contrast for nanoplates grown on oxidized silicon (300 nm SiO2/Si). As a new member of TI nanomaterials, ultrathin TI nanoplates have an extremely large surface-to-volume ratio and can be electrically gated more effectively than the bulk form, potentially enhancing surface state effects in transport measurements. Low-temperature transport measurements of a single nanoplate device, with a high-k dielectric top gate, show decrease in carrier concentration by several times and large tuning of chemical potential. © 2010 American Chemical Society.},
   author = {Desheng Kong and Wenhui Dang and Judy J. Cha and Hui Li and Stefan Meister and Hailin Peng and Zhongfan Liu and Yi Cui},
   doi = {10.1021/NL101260J/SUPPL_FILE/NL101260J_SI_001.PDF},
   issn = {15306984},
   issue = {6},
   journal = {Nano Letters},
   keywords = {Bismuth selenide,Bismuth telluride,Nanoplate,Topological insulator},
   month = {6},
   pages = {2245-2250},
   publisher = { American Chemical Society},
   title = {Few-layer nanoplates of {Bi$_2$Se$_3$} and {Bi$_2$Te$_3$} with highly tunable chemical potential},
   volume = {10},
   url = {https://pubs.acs.org/doi/full/10.1021/nl101260j},
   year = {2010}
}
@article{Ju2019,
   abstract = {Topological insulators (TIs) are a class of materials that can exhibit robust spin polarizations at the surfaces and have attracted much attention toward spintronic applications. Here, we optimized a solution route to synthesize ultrathin Bi2Se3 and Sb-doped Bi2Se3 nanoplates with a thickness of 6-15 nm and an average lateral size around 5 μm, up to a maximum of 10 μm. Solution chemistry provides high quality nanoplates of TIs with options to manipulate the surface states. We have synthesized Bi2Se3 and Sb-doped Bi2Se3 and characterized single nanoplates. Sb doping is used to suppress the bulk carriers, and an atomic percentage μ6% of Sb is demonstrated by energy dispersive X-ray spectroscopy (EDS). The 2D electron carrier concentration for Sb-doped Bi2Se3 nanoplates is lowered to 5.5 × 1012 cm-2, reducing the concentration by a factor of 3 compared to the undoped Bi2Se3 nanoplate sample with an average 2D carrier concentration of 16 × 1012 cm-2. At 2 K, the pronounced ambipolar field effect is observed on the low-carrier-density Sb-doped Bi2Se3 nanoplates, further demonstrating the flexible manipulation of carrier type and concentration for these single-crystal nanoplates. Large out-of-plane magnetoresistance is measured, with a gate tunable phase coherence length.},
   author = {Zheng Ju and Yasen Hou and Andrew Bernard and Valentin Taufour and Dong Yu and Susan M. Kauzlarich},
   doi = {10.1021/ACSAELM.9B00415/ASSET/IMAGES/MEDIUM/EL9B00415_M001.GIF},
   issn = {26376113},
   issue = {9},
   journal = {ACS Applied Electronic Materials},
   keywords = {Sb-doped Bi2Se3,ambipolar field effect,larger lateral size,low carrier concentration,magnetoresistance,solution synthesis},
   month = {9},
   pages = {1917-1923},
   publisher = {American Chemical Society},
   title = {Ambipolar Topological Insulator and High Carrier Mobility in Solution Grown Ultrathin Nanoplates of Sb-Doped Bi2Se3},
   volume = {1},
   url = {https://pubs.acs.org/doi/full/10.1021/acsaelm.9b00415},
   year = {2019}
}
@article{Yashina2013,
   abstract = {The long-term stability of functional properties of topological insulator materials is crucial for the operation of future topological insulator based devices. Water and oxygen have been reported to be the main sources of surface deterioration by chemical reactions. In the present work, we investigate the behavior of the topological surface states on Bi2X3 (X = Se, Te) by valence-band and core level photoemission in a wide range of water and oxygen pressures both in situ (from 10-8 to 0.1 mbar) and ex situ (at 1 bar). We find that no chemical reactions occur in pure oxygen and in pure water. Water itself does not chemically react with both Bi2Se 3 and Bi2Te3 surfaces and only leads to slight p-doping. In dry air, the oxidation of the Bi2Te3 surface occurs on the time scale of months, in the case of Bi2Se3 surface of cleaved crystal, not even on the time scale of years. The presence of water, however, promotes the oxidation in air, and we suggest the underlying reactions supported by density functional calculations. All in all, the surface reactivity is found to be negligible, which allows expanding the acceptable ranges of conditions for preparation, handling and operation of future Bi 2X3-based devices. © 2013 American Chemical Society.},
   author = {Lada V. Yashina and Jaime Sánchez-Barriga and Markus R. Scholz and Andrey A. Volykhov and Anna P. Sirotina and Vera S. Neudachina and Marina E. Tamm and Andrei Varykhalov and Dmitry Marchenko and Gunther Springholz and Günther Bauer and Axel Knop-Gericke and Oliver Rader},
   doi = {10.1021/NN400908B/SUPPL_FILE/NN400908B_SI_001.PDF},
   issn = {19360851},
   issue = {6},
   journal = {ACS Nano},
   keywords = {angle-resolved photoemission,high-pressure XPS,surface reactivity,topological insulators,topological surface states},
   month = {6},
   pages = {5181-5191},
   publisher = {American Chemical Society},
   title = {Negligible surface reactivity of topological insulators {Bi$_2$Se$_3$} and {Bi$_2$Te$_3$} towards oxygen and water},
   volume = {7},
   url = {https://pubs.acs.org/doi/full/10.1021/nn400908b},
   year = {2013}
}
@article{Figueroa2016,
   abstract = {The breaking of time-reversal symmetry (TRS) in topological insulators is a prerequisite for unlocking their exotic properties and for observing the quantum anomalous Hall effect (QAHE). The incorporation of dopants which exhibit magnetic long-range order is the most promising approach for TRS-breaking. REBiTe3, wherein 50% of the Bi is substitutionally replaced by a RE atom (RE = Gd, Dy, and Ho), is a predicted QAHE system. Despite the low solubility of REs in bulk crystals of a few %, highly doped thin films have been demonstrated, which are free of secondary phases and of high crystalline quality. Here we study the effects of exposure to atmosphere of rare earth-doped Bi2(Se, Te)3 thin films using x-ray absorption spectroscopy. We demonstrate that these RE dopants are all trivalent and effectively substitute for Bi3+ in the Bi2(Se, Te)3 matrix. We find an unexpected high degree of sample oxidation for the most highly doped samples, which is not restricted to the surface of the films. In the low-doping limit, the RE-doped films mostly show surface oxidation, which can be prevented by surface passivation, encapsulation, or in-situ cleaving to recover the topological surface state.},
   author = {A. I. Figueroa and G. Van Der Laan and S. E. Harrison and G. Cibin and T. Hesjedal},
   doi = {10.1038/srep22935},
   issn = {2045-2322},
   issue = {1},
   journal = {Scientific Reports 2016 6:1},
   keywords = {Materials for devices,Topological matter},
   month = {3},
   pages = {1-9},
   publisher = {Nature Publishing Group},
   title = {Oxidation Effects in Rare Earth Doped Topological Insulator Thin Films},
   volume = {6},
   url = {https://www.nature.com/articles/srep22935},
   year = {2016}
}
@article{Benia2011,
   abstract = {Using angular resolved photoemission spectroscopy we studied the evolution of the surface electronic structure of the topological insulator Bi 2Se3 as a function of water vapor exposure. We find that a surface reaction with water induces a band bending, which shifts the Dirac point deep into the occupied states and creates quantum well states with a strong Rashba-type splitting. The surface is thus not chemically inert, but the topological state remains protected. The band bending is traced back to Se abstraction, leaving positively charged vacancies at the surface. Because of the presence of water vapor, a similar effect takes place when Bi 2Se3 crystals are left in vacuum or cleaved in air, which likely explains the aging effect observed in the Bi2Se3 band structure. © 2011 American Physical Society.},
   author = {Hadj M. Benia and Chengtian Lin and Klaus Kern and Christian R. Ast},
   doi = {10.1103/PHYSREVLETT.107.177602/SUPMAT.PDF},
   issn = {00319007},
   issue = {17},
   journal = {Physical Review Letters},
   month = {10},
   pages = {177602},
   publisher = {American Physical Society},
   title = {Reactive chemical doping of the {Bi$_2$Se$_3$} topological insulator},
   volume = {107},
   url = {https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.107.177602},
   year = {2011}
}
@article{Jiang2019,
   abstract = {Broadband transient reflectivity traces were measured for Bi2Se3 thin films with various substrates via a 400 nm pump–white-light-probe setup. We have verified the existence of a second Dirac surface state in Bi2Se3 and qualitatively located it by properly analyzing the traces acquired at different probe wavelengths. Referring to the band structure of Bi2Se3, the relaxation mechanisms for photo-excited electrons with different energies are also revealed and studied. Our results show a second rise of the transient reflection signal at the time scale of several picoseconds. The types of substrate can also significantly affect the dynamics of the rising signal. This phenomenon is attributed to the effect of lattice heating and coherent phonon processes. The mechanism study in this work will benefit the fabrication of high-performance photonic devices based on topological insulators.},
   author = {Tian Jiang and Tian Jiang and Tian Jiang and Runlin Miao and Jie Zhao and Zhongjie Xu and Tong Zhou and Ke Wei and Jie You and Xin Zheng and Zhenyu Wang and Xiang'ai Cheng},
   issue = {2},
   journal = {Chinese Optics Letters, Vol. 17, Issue 2, pp. 020005-},
   keywords = {Bismuth,Photonic devices,Reflection,Reflectivity,Surfaces,Thin films},
   month = {2},
   pages = {020005-},
   publisher = {Chinese Optical Society},
   title = {Electron–phonon coupling in topological insulator {Bi$_2$Se$_3$} thin films with different substrates},
   volume = {17},
   url = {https://opg.optica.org/abstract.cfm?uri=col-17-2-020005 https://opg.optica.org/col/abstract.cfm?uri=col-17-2-020005},
   year = {2019}
}
@article{Checkelsky2014,
   abstract = {Quantized resistivity values for 2D electron systems don’t necessarily result from an external magnetic field as in the ‘normal’ quantum Hall effect; they can arise due to a material's intrinsic ferromagnetism too—the quantum anomalous Hall effect. Experiments with a ferromagnetic topological insulator now establish how the anomalous states can be mapped onto the normal states. Topological insulators are bulk electronic insulators with symmetry-protected gapless modes on their surfaces1,2,3,4,5. Breaking time-reversal symmetry in these systems via ferromagnetism induces a gapped state characterized by a zero magnetic field quantized Hall response—the quantum anomalous Hall (QAH) state6,7,8. A key question that has remained experimentally unexplored is the relationship of this new type of quantum Hall (QH) state with the previously known orbitally driven QH states. Here, we show experimentally that a ferromagnetic topological insulator exhibiting the QAH state is well described by the global phase diagram of the QH effect. By mapping the conductivity tensor in the vicinity of the QAH phase, we find evidence for quantum criticality and delocalization behaviour9,10 that can quantitatively be described by the renormalization group properties of the QH ground state11,12. This result demonstrates that this QAH state can be understood within the context of the law of corresponding states that governs the QH state13,14.},
   author = {J. G. Checkelsky and R. Yoshimi and A. Tsukazaki and K. S. Takahashi and Y. Kozuka and J. Falson and M. Kawasaki and Y. Tokura},
   doi = {10.1038/nphys3053},
   issn = {1745-2481},
   issue = {10},
   journal = {Nature Physics 2014 10:10},
   keywords = {Quantum Hall,Topological matter},
   month = {8},
   pages = {731-736},
   publisher = {Nature Publishing Group},
   title = {Trajectory of the anomalous Hall effect towards the quantized state in a ferromagnetic topological insulator},
   volume = {10},
   url = {https://www.nature.com/articles/nphys3053},
   year = {2014}
}
@article{Yang2014,
   abstract = {The tunability of the chemical potential for a wide range encompassing the Dirac point is important for many future devices based on topological insulators. Here, we report a method to fabricate highly efficient top gates on epitaxially grown (Bi1-xSbx)2Te3 topological insulator thin films without degrading the film quality. By combining an in situ deposited Al2O3 capping layer and a SiNx dielectric layer deposited at low temperature, we were able to protect the films from degradation during the fabrication processes. We demonstrate that by using this top gate, the carriers in the top surface can be efficiently tuned from n- to p-type. We also show that magnetotransport properties give evidence for decoupled transport through top and bottom surfaces for the entire range of gate voltage, which is only possible in truly bulk-insulating samples. © 2014 AIP Publishing LLC.},
   author = {Fan Yang and A. A. Taskin and Satoshi Sasaki and Kouji Segawa and Yasuhide Ohno and Kazuhiko Matsumoto and Yoichi Ando},
   doi = {10.1063/1.4873397/131134},
   issn = {00036951},
   issue = {16},
   journal = {Applied Physics Letters},
   month = {4},
   pages = {161614},
   publisher = {American Institute of Physics Inc.},
   title = {Top gating of epitaxial {(Bi$_{1-x}$Sb$_x$)$_2$Te$_3$} topological insulator thin films},
   volume = {104},
   url = {/aip/apl/article/104/16/161614/131134/Top-gating-of-epitaxial-Bi1-xSbx-2Te3-topological},
   year = {2014}
}
@inproceedings{Kamboj2018,
   abstract = {The surface of a topological insulator harbors exotic topological states, protected against backscattering from disorder by time reversal symmetry. The study of these exotic quantum states not only provides an opportunity to explore fundamental phenomena in condensed matter physics, such as the spin Hall effect, but also lays the foundation for applications from quantum computing to spintronics. Conventional electrical measurements suffer from substantial bulk interference, making it difficult to clearly distinguish topological surface states from bulk states. Employing terahertz time-domain spectroscopy, we study the temperature-dependent optical behavior of a 23-quintuple-thick film of bismuth selenide (Bi<sub>2</sub>Se<sub>3</sub>) allowing for the deconvolution of the surface state response from the bulk. Our measurement of carrier dynamics give an optical mobility exceeding 2100 cm<sup>2</sup>/V&bull;s at 4 K, indicative of a surface-dominated response, and a scattering lifetime of ~0.18 ps and a carrier density of 6×10<sup>12</sup> cm<sup>-2</sup> at 4 K for the Bi<sub>2</sub>Se<sub>3</sub> film. The sample was further processed into a Hall bar device using two different etching techniques, a wet chemical etching and Ar<sup>+</sup> ion milling, which resulting in a reduced Hall mobility. Even so, the magneto-conductance transport reveals weak antilocalization behavior in our Bi<sub>2</sub>Se3 sample, consistent with the presence of a single topological surface state mode.},
   author = {Varun S. Kamboj and Angadjit Singh and Thierry Ferrus and Harvey E. Beere and Liam B. Duffy and Thorsten Hesjedal and Crispin H. W. Barnes and David A. Ritchie},
   doi = {10.1117/12.2289116},
   isbn = {9781510615472},
   issn = {1996756X},
   booktitle = {Proc. SPIE 10531, Terahertz, RF, Millimeter, and Submillimeter-Wave Technology and Applications XI},
   keywords = {Bismuth,Etching,Magnetism,Scattering,Terahertz radiation,Thin films,Wet etching},
   month = {2},
   pages = {73-82},
   publisher = {SPIE},
   title = {{THz} carrier dynamics and magnetotransport study of topological surface states in thin film {Bi$_2$Se$_3$}},
   volume = {10531},
   url = {https://www.spiedigitallibrary.org/conference-proceedings-of-spie/10531/105310I/THz-carrier-dynamics-and-magnetotransport-study-of-topological-surface-states/10.1117/12.2289116.full https://www.spiedigitallibrary.org/conference-proceedings-of-spie/10531/105310I/THz-carrier-dynamics-and-magnetotransport-study-of-topological-surface-states/10.1117/12.2289116.short},
   year = {2018}
}
@article{Cayron2021,
   abstract = {Recently, a hexagonal phase has been reported in high carbon steels in several studies. Here, we show that the electron microscopy results used in these studies were erroneously interpreted. The extra-spots in the diffraction patterns and the odd contrasts in the high resolution images are not those a superstructure but result from double diffraction and streaking effects due to the presence of twins and stacking faults. We point out a similar unfortunate misunderstanding of these effects in papers reporting the existence of a 9R structure in aluminium or copper, or exotic forms of carbon in diamonds.},
   author = {Cyril Cayron},
   doi = {10.1016/j.scriptamat.2020.11.014},
   issn = {13596462},
   journal = {Scripta Materialia},
   month = {3},
   publisher = {Acta Materialia Inc},
   title = {Diffraction artefacts from twins and stacking faults, and the mirage of hexagonal, polytypes or other superstructures},
   volume = {194},
   year = {2021}
}
@article{Wang2011,
   abstract = {A differential coupling of topological surface states to left- versus right-circularly polarized light is the basis of many optospintronics applications of topological insulators. Here we report direct evidence of circular dichroism from the surface states of Bi2Se3 using laser-based time-of-flight angle-resolved photoemission spectroscopy. By employing a novel sample rotational analysis, we resolve unusual modulations in the circular dichroism photoemission pattern as a function of both energy and momentum, which perfectly mimic the predicted but hitherto unobserved three-dimensional warped spin texture of the surface states. By developing a microscopic theory of photoemission from topological surface states, we show that this correlation is a natural consequence of spin-orbit coupling. These results suggest that our technique may be a powerful probe of the spin texture of spin-orbit coupled materials in general. © 2011 American Physical Society.},
   author = {Y. H. Wang and D. Hsieh and D. Pilon and L. Fu and D. R. Gardner and Y. S. Lee and N. Gedik},
   doi = {10.1103/PhysRevLett.107.207602},
   issn = {00319007},
   journal = {Physical Review Letters},
   month = {11},
   title = {Observation of a warped helical spin texture in Bi2Se 3 from circular dichroism angle-resolved photoemission spectroscopy},
   volume = {107},
   year = {2011}
}
@inproceedings{Kamboj2018,
   abstract = {© 2018 SPIE. The surface of a topological insulator harbors exotic topological states, protected against backscattering from disorder by time reversal symmetry. The study of these exotic quantum states not only provides an opportunity to explore fundamental phenomena in condensed matter physics, such as the spin Hall effect, but also lays the foundation for applications from quantum computing to spintronics. Conventional electrical measurements suffer from substantial bulk interference, making it difficult to clearly distinguish topological surface states from bulk states. Employing terahertz time-domain spectroscopy, we study the temperature-dependent optical behavior of a 23-quintuple-thick film of bismuth selenide (Bi2Se3) allowing for the deconvolution of the surface state response from the bulk. Our measurement of carrier dynamics give an optical mobility exceeding 2100 cm2/V•s at 4 K, indicative of a surface-dominated response, and a scattering lifetime of ∼0.18 ps and a carrier density of 6×1012 cm-2 at 4 K for the Bi2Se3 film. The sample was further processed into a Hall bar device using two different etching techniques, a wet chemical etching and Ar+ ion milling, which resulting in a reduced Hall mobility. Even so, the magneto-conductance transport reveals weak antilocalization behavior in our Bi2Se3 sample, consistent with the presence of a single topological surface state mode.},
   author = {Varun S. Kamboj and Angadjit Singh and Thierry Ferrus and Harvey E. Beere and Liam B. Duffy and Thorsten Hesjedal and Crispin H. W. Barnes and David A. Ritchie},
   doi = {10.1117/12.2289116},
   issn = {1996756X},
   month = {2},
   pages = {18},
   publisher = {SPIE-Intl Soc Optical Eng},
   title = {THz carrier dynamics and magnetotransport study of topological surface states in thin film Bi2Se3},
   year = {2018}
}
@article{JJBurton2025,
   author = {J.J.Burton and C.S.Knox and A.Yagmur and I.Gelen and M.D.Rogers and P.M.Shepley and M.Ali and J.R.Freeman and S.Sasaki and B.J.Hickey},
   journal = {In Preparation},
   title = {The Spin-Orbit Lifetime and Electron-Electron Interactions in {Bi$_2$Se$_3$}},
   year = {2025}
}
@article{King2011,
   abstract = {We report a Rashba spin splitting of a two-dimensional electron gas in the topological insulator Bi2Se3 from angle-resolved photoemission spectroscopy. We further demonstrate its electrostatic control, and show that spin splittings can be achieved which are at least an order-of-magnitude larger than in other semiconductors. Together these results show promise for the miniaturization of spintronic devices to the nanoscale and their operation at room temperature. © 2011 American Physical Society.},
   author = {P. D.C. King and R. C. Hatch and M. Bianchi and R. Ovsyannikov and C. Lupulescu and G. Landolt and B. Slomski and J. H. Dil and D. Guan and J. L. Mi and E. D.L. Rienks and J. Fink and A. Lindblad and S. Svensson and S. Bao and G. Balakrishnan and B. B. Iversen and J. Osterwalder and W. Eberhardt and F. Baumberger and Ph Hofmann},
   doi = {10.1103/PhysRevLett.107.096802},
   issn = {00319007},
   issue = {9},
   journal = {Physical Review Letters},
   month = {8},
   title = {Large Tunable Rashba Spin Splitting of a Two-Dimensional Electron Gas in {Bi$_2$Se$_3$}},
   volume = {107},
   year = {2011}
}
@article{Coiras2022,
   abstract = {In this work, we performed laser annealing of thin Sb2Te3 films to optimize crystallization time and their nonlinear optical properties. The annealed layers were studied by electron microscopy and UV–Vis spectrophotometry. Their nonlinear optical response was investigated by nonlinear transmission and Z-scan measurements. These studies were performed by a femtosecond laser system providing 400 fs laser pulses at 1030 nm. The results were compared with previous findings based on studies of oven-annealed thin films.},
   author = {Delphine Coiras and Richard Nicolas Verrone and Andrea Campos and Martiane Cabié and Laurent Gallais and Marco Minissale and Julien Lumeau and Jean Yves Natoli and Konstantinos Iliopoulos},
   doi = {10.3390/opt3030023},
   issn = {26733269},
   journal = {Optics},
   month = {9},
   pages = {234-242},
   publisher = {MDPI},
   title = {Laser Annealing of {Sb$_2$Te$_3$} 2D Layers towards Nonlinear Optical Applications},
   volume = {3},
   year = {2022}
}
@article{Liu2019-2,
   abstract = {Sb-based chalcogenide materials are important for nonlinear devices due to their giant optical nonlinearities even at low irradiance intensities. In this study, the linear optical properties and nonlinear absorption behaviors of two typical Sb-based chalcogenides, Sb2Se3 and Sb2Te3 were systematically studied. The measurements of linear optical properties show that the metallic character of Sb2Te3 is much stronger than that of Sb2Se3. For nonlinear absorption properties, both Sb2Se3 and Sb2Te3 thin films exhibit saturable absorption responses but Sb2Te3 has larger modulation depth. The giant NOA behaviors are attributed to the competition between ground state excitation and excited state absorption. Theoretical calculations reveal that these two materials have large nonlinear absorption coefficients, implying that they are promising materials for innovative ultrafast nonlinear optical devices.},
   author = {Chunmin Liu and Ling Cheng and Yafei Yuan and Jing Su and Xintong Zhang and Xiangxiang Li and Haibin Zhao and Hao Zhang and Yuxiang Zheng and Jing Li},
   doi = {10.1088/2053-1591/ab23b0},
   issn = {20531591},
   journal = {Materials Research Express},
   publisher = {Institute of Physics Publishing},
   title = {Contrastive investigation on linear optical properties and nonlinear absorption behaviors between {Sb$_2$Se$_3$} and {Sb$_2$Te$_3$} thin films},
   volume = {6},
   year = {2019}
}
@article{Uklein2018,
   abstract = {The nonlinear optical (NLO) properties of native defect-rich ZnO single crystals were studied in details within the excitation of the continuous wave (CW) and pulsed laser radiation at 532 nm (2.33 eV). Analysis of the experimental data of optical elastic scattering, Fourier transform infrared (FTIR), near infrared–visible–ultraviolet (NIR–Vis–UV) spectra recorded in reflection and absorption modes, and data of photoluminescence (PL) spectroscopy confirmed the contribution of both intrinsic defects and their clusters, being determined before by neutron diffraction and XRD analysis. It was shown that the high sensitivity of the NLO diagnostics via self-action of a laser beam is due to the resonant excitation of the deep defects states at wavelength 532 nm. It was also demonstrated the correlation of the real and imaginary parts of the cubic NLO susceptibility with PL and FTIR spectroscopies data dealing with the defect bands manifestation, while the elastic optical scattering and Vis-NIR spectroscopy data – with the intrinsic defect content. High photoinduced polarizabilities of the excited states provide application of the refractive NLO response and the optical elastic scattering indicatrices analysis as an express nondestructive technique to reveal the deep defects content in the bulk ZnO.},
   author = {A. V. Uklein and V. V. Multian and G. M. Kuz'micheva and R. P. Linnik and V. V. Lisnyak and A. I. Popov and V. Ya Gayvoronsky},
   doi = {10.1016/j.optmat.2018.08.001},
   issn = {09253467},
   journal = {Optical Materials},
   month = {10},
   pages = {738-747},
   publisher = {Elsevier B.V.},
   title = {Nonlinear optical response of bulk {ZnO} crystals with different content of intrinsic defects},
   volume = {84},
   year = {2018}
}
@article{Bragaglia2020,
   abstract = {In this study we report on the investigation of epitaxially grown Sb2Te3 by employing Fourier-Transform transmission Spectroscopy (FTS) with laser-induced Coherent Synchrotron Radiation (CSR) in the Terahertz (THz) spectral range. Static spectra in the range between 20 and 120 cm−1 highlight a peculiar softening of an in-plane IR-active phonon mode upon temperature decrease, as opposed to all Raman active modes which instead show a hardening upon temperature decrease in the same energy range. The phonon mode softening is found to be accompanied by an increase of free carrier concentration. A strong coupling of the two systems (free carriers and phonons) is observed and further evidenced by exciting the same phonon mode at 62 cm−1 within an ultrafast pump-probe scheme employing a femtosecond laser as pump and a CSR single cycle THz pulse as probe. Separation of the free carrier contribution and the phonon resonance in the investigated THz range reveals that, both damping of the phonon mode and relaxation of hot carriers in the time domain happen on the same time scale of 5 ps. This relaxation is about a factor of 10 slower than expected from the Lorentz time-bandwidth limit. The results are discussed in the framework of phonon scattering at thermal and laser induced transient free carriers.},
   author = {V. Bragaglia and M. Ramsteiner and D. Schick and J. E. Boschker and R. Mitzner and R. Calarco and K. Holldack},
   doi = {10.1038/s41598-020-69663-y},
   issn = {20452322},
   journal = {Scientific Reports},
   month = {12},
   pmid = {32737341},
   publisher = {Nature Research},
   title = {Phonon anharmonicities and ultrafast dynamics in epitaxial {Sb$_2$Te$_3$}},
   volume = {10},
   year = {2020}
}
@article{Moisset2020,
   abstract = {The optimization of thin Sb2Te3 films in order to obtain giant ultrafast optical nonlinearities is reported. The ultrafast nonlinearities of the thin film layers are studied by the Z-scan technique. Giant saturable absorption is obtained, which is the highest ever reported, by means of the Z-scan technique.},
   author = {Charles Moisset and Richard Nicolas Verrone and Antoine Bourgade and Gebrehiwot Tesfay Zeweldi and Marco Minissale and Laurent Gallais and Carine Perrin-Pellegrino and Hassan Akhouayri and Julien Lumeau and Jean Yves Natoli and Konstantinos Iliopoulos},
   doi = {10.1039/c9na00796b},
   issn = {25160230},
   journal = {Nanoscale Advances},
   month = {4},
   pages = {1427-1430},
   publisher = {Royal Society of Chemistry},
   title = {Giant ultrafast optical nonlinearities of annealed {Sb$_2$Te$_3$} layers},
   volume = {2},
   year = {2020}
}
@article{Ye2011,
   abstract = {We studied the Ag-intercalated 3D topological insulator Bi$_{2}$Se$_{3}$ by scanning tunneling microscopy/spectroscopy and angle-resolved photoemission spectroscopy, combined with a first principles calculations. We demonstrate that silver atoms deposited on the surface of Bi$_{2}$Se$_{3}$ are intercalated between the quintuple layer (QL) units of the crystal, causing a expansion of the van der Waals gaps and the detachment of topmost QLs from the bulk crystal. This leads to a relocation (in the real space) of the the topological state beneath the detached quintuple layers, accompanied by the emergence of parabolic and "M-shaped" trivial bands localized above the relocated topological states. These novel findings open a pathway to the engineering of Dirac fermions shielded from the ambient contamination and may facilitate the realization of fault-tolerant quantum devices.},
   author = {M. Ye and S. V. Eremeev and K. Kuroda and M. Nakatake and S. Kim and Y. Yamada and E. E. Krasovskii and E. V. Chulkov and M. Arita and H. Miyahara and T. Maegawa and K. Okamoto and K. Miyamoto and T. Okuda and K. Shimada and H. Namatame and M. Taniguchi and Y. Ueda and A. Kimura},
   month = {12},
   title = {Relocation of the topological surface state of Bi$_{2}$Se$_{3}$ beneath the surface by Ag intercalation},
   year = {2011}
}
@article{Scholz2011,
   abstract = {Topological insulators have been successfully identified by spin-resolved photoemission but the spin polarization remained low (~20%). We show for Bi2Te3 that the in-gap surface state is much closer to full spin polarization with measured values reaching 80% at the Fermi level. When hybridizing with the bulk it remains highly spin polarized which may explain recent unusual quantum interference results on Bi2Se3. The topological surface state shows a large circular dichroism in the photoelectron angle distribution with an asymmetry of ~20% the sign of which corresponds to that of the measured spin.},
   author = {M. R. Scholz and J. Sánchez-Barriga and D. Marchenko and A. Varykhalov and A. Volykhov and L. V. Yashina and O. Rader},
   month = {8},
   title = {High spin polarization and circular dichroism of topological surface states on {Bi$_2$Te$_3$}},
   year = {2011}
}
@article{Ye2011,
   abstract = {We studied the Ag-intercalated 3D topological insulator Bi$_{2}$Se$_{3}$ by scanning tunneling microscopy/spectroscopy and angle-resolved photoemission spectroscopy, combined with a first principles calculations. We demonstrate that silver atoms deposited on the surface of Bi$_{2}$Se$_{3}$ are intercalated between the quintuple layer (QL) units of the crystal, causing a expansion of the van der Waals gaps and the detachment of topmost QLs from the bulk crystal. This leads to a relocation (in the real space) of the the topological state beneath the detached quintuple layers, accompanied by the emergence of parabolic and "M-shaped" trivial bands localized above the relocated topological states. These novel findings open a pathway to the engineering of Dirac fermions shielded from the ambient contamination and may facilitate the realization of fault-tolerant quantum devices.},
   author = {M. Ye and S. V. Eremeev and K. Kuroda and M. Nakatake and S. Kim and Y. Yamada and E. E. Krasovskii and E. V. Chulkov and M. Arita and H. Miyahara and T. Maegawa and K. Okamoto and K. Miyamoto and T. Okuda and K. Shimada and H. Namatame and M. Taniguchi and Y. Ueda and A. Kimura},
   month = {12},
   title = {Relocation of the topological surface state of Bi$_{2}$Se$_{3}$ beneath the surface by Ag intercalation},
   year = {2011}
}
@article{Scholz2011,
   abstract = {Topological insulators have been successfully identified by spin-resolved photoemission but the spin polarization remained low (~20%). We show for Bi2Te3 that the in-gap surface state is much closer to full spin polarization with measured values reaching 80% at the Fermi level. When hybridizing with the bulk it remains highly spin polarized which may explain recent unusual quantum interference results on Bi2Se3. The topological surface state shows a large circular dichroism in the photoelectron angle distribution with an asymmetry of ~20% the sign of which corresponds to that of the measured spin.},
   author = {M. R. Scholz and J. Sánchez-Barriga and D. Marchenko and A. Varykhalov and A. Volykhov and L. V. Yashina and O. Rader},
   month = {8},
   title = {High spin polarization and circular dichroism of topological surface states on {Bi$_2$Te$_3$}},
   year = {2011}
}
@article{Plucinski2013,
   abstract = {We have performed a combined spectroscopy and microscopy study on surfaces of Sb2Te3/Si(111) thin films exposed to air and annealed under ultra-high vacuum conditions. Scanning tunneling microscopy images, with atomic resolution present in most areas of such processed surfaces, show a significant amount of impurities and defects. Scanning tunneling spectroscopy reveals the bulk band gap of ∼ 170 meV centered ∼ 65 meV above the Fermi level. This intrinsic p-type doping behavior is confirmed by high-resolution angle-resolved photoemission spectra, which show the dispersions of the lower Dirac cone and the spectral weight of the bulk valence bands crossing the Fermi level. Spin-polarized photoemission revealed up to ∼15% in-plane spin polarization for photoelectrons related to the topologically protected Dirac cone states near the Fermi level, and up to ∼40% for several states at higher binding energies. The results are interpreted using ab initio electronic structure simulations and confirm the robustness of the time-reversal symmetry protected topological surface states in Sb2 Te3 in the presence of impurities and defects. © 2013 American Institute of Physics.},
   author = {L. Plucinski and A. Herdt and S. Fahrendorf and G. Bihlmayer and G. Mussler and S. Döring and J. Kampmeier and F. Matthes and D. E. Bürgler and D. Grützmacher and S. Blügel and C. M. Schneider},
   doi = {10.1063/1.4789353},
   issn = {00218979},
   issue = {5},
   journal = {Journal of Applied Physics},
   month = {2},
   title = {Electronic structure, surface morphology, and topologically protected surface states of {Sb$_2$Te$_3$} thin films grown on {Si(111)}},
   volume = {113},
   year = {2013}
}
@article{Pauly2012,
   abstract = {Using high-resolution spin- and angle-resolved photoemission spectroscopy, we map the electronic structure and spin texture of the surface states of the topological insulator Sb2Te3. In combination with density functional calculations (DFT), we directly show that Sb2Te 3 exhibits a partially occupied, single spin-Dirac cone around the Fermi energy EF, which is topologically protected. DFT obtains a spin polarization of the occupied Dirac cone states of 80-90%, which is in reasonable agreement with the experimental data after careful background subtraction. Furthermore, we observe a strongly spin-orbit split surface band at lower energy. This state is found at E-EF -0.8 eV at the Γ̄ point, disperses upward, and disappears at about E-E F=-0.4 eV into two different bulk bands. Along the Γ̄-K̄ direction, the band is located within a spin-orbit gap. According to an argument given by Pendry and Gurman in 1975, such a gap must contain a surface state, if it is located away from the high-symmetry points of the Brillouin zone. Thus, the novel spin-split state is protected by symmetry, too. © 2012 American Physical Society.},
   author = {C. Pauly and G. Bihlmayer and M. Liebmann and M. Grob and A. Georgi and D. Subramaniam and M. R. Scholz and J. Sánchez-Barriga and A. Varykhalov and S. Blügel and O. Rader and M. Morgenstern},
   doi = {10.1103/PhysRevB.86.235106},
   issn = {10980121},
   issue = {23},
   journal = {Physical Review B - Condensed Matter and Materials Physics},
   month = {12},
   title = {Probing two topological surface bands of {Sb$_2$Te$_3$} by spin-polarized photoemission spectroscopy},
   volume = {86},
   year = {2012}
}
@article{Shimizu2012,
   abstract = {Topological insulators are quantum materials comprised of an insulating bulk gap and topologically protected metallic surfaces with a Dirac-like band dispersion. To access the Dirac point by transport measurements is a very challenging issue faced in current investigations of these materials. Here we report the electronic state modulation in topological insulator (Bi 1-xSb x) 2Te 3 thin films by means of an ionic-liquid gating. The films with 20 nm thickness were grown on lattice-matched semi-insulating InP substrates by molecular beam epitaxy; the temperature dependencies of resistance of these films clearly indicate their insulating bulk and metallic surface characteristics. The surface state carriers were systematically controlled by using electric-double-layer transistor (EDLT) configurations with ionic-liquid dielectrics. It was demonstrated that the surface state in the (Bi 1-xSb x) 2Te 3-based EDLTs is tuned across the Dirac point, showing ambipolar transport in a topological transport regime. © 2012 American Physical Society.},
   author = {Sunao Shimizu and Ryutaro Yoshimi and Takafumi Hatano and Kei S. Takahashi and Atsushi Tsukazaki and Masashi Kawasaki and Yoshihiro Iwasa and Yoshinori Tokura},
   doi = {10.1103/PhysRevB.86.045319},
   issn = {10980121},
   issue = {4},
   journal = {Physical Review B - Condensed Matter and Materials Physics},
   month = {7},
   title = {Gate control of surface transport in MBE-grown topological insulator (Bi$_{(1-x)}$Sb$_x$)$_2$Te$_3$ thin films},
   volume = {86},
   year = {2012}
}
