1. ABOUT THE DATASET -------------------- Title: Creator(s): [Craig S. Knox, Matthew T. Vaughan, Nathan R. Fox, Ahmet Yagmur, Satoshi Sasaki, John E. Cunningham, Edmund H. Linfield, Alexander Giles Davies and Joshua R. Freeman] Organisation(s): [University of Leeds] Publication Year: 2024 Description: [This is the dataset associated with the study performed on the transport and FIR properties of a a Topologically insulating Bi$_2$Se$_3$ sample. It contains THz and DC conductivity data that show the change in conductivity as a function of gate bias, displaying the robustness of the topological surface states against external perturbation.] Cite as: [Craig S. Knox, Matthew T. Vaughan, Nathan R. Fox, Ahmet Yagmur, Satoshi Sasaki, John E. Cunningham, Edmund H. Linfield, A. Giles Davies, Joshua R. Freeman (2024): Dataset Associated with Optical Conductivity of a Bi2Se3 Topological Insulator with a THz Transparent Top Gate. [Dataset]. https://doi.org/10.5518/1475] Related publication: [Optical Conductivity of a Bi2Se3 Topological Insulator with a THz Transparent Top Gate, By; Craig S. Knox, Matthew T. Vaughan, Nathan R. Fox, Ahmet Yagmur, Satoshi Sasaki, John E. Cunningham, Edmund H. Linfield, Alexander Giles Davies and Joshua R. Freeman, Nanophotonics, 2024, 10.1515/nanoph-2023-0690] Contact: [C.S.Knox@leeds.ac.uk] 2. TERMS OF USE --------------- [This dataset is licensed under a Creative Commons Attribution 4.0 International Licence: https://creativecommons.org/licenses/by/4.0/.] 3. PROJECT AND FUNDING INFORMATION ---------------------------------- Title 1:[NAME] Funding organisation: [UKRI] Grant no.:[EP/P021859/1] Title 2:[EXTREME-IR] Funding organisation: [European Union’s Horizon 2020 research and innovation program] Grant no.:[964735] Title 3:[Sir Henry Royce Institute - Leeds Equipment] Funding organisation: [Henry Royce Institute] Grant no.:[EP/P022464/1] Titel 4:[Sir Henry Royce Institute - recurrent grant] Funding organisation: [Henry Royce Institute] Grant no.: [EP/R00661X/1] 4. CONTENTS ----------- File listing [The data as seen in the paper is collected in 2 Origin projects (Figures_1_and_2.opju, and Figures_3_4_and_5.opju), where each graph is labelled according to the figure part it represents. Additionally, Figures_1_and_2.opju is plit into 12 folders, where each folder contains either the data and analysis associated with a single gate voltage (+5V,+4V,+3V,+2V,+1V,0V,-1V,-2V,-3V,-4V,-5V) or is the collection of data associated with the analysis (Two_Carrier_Fitting and __Overview). Figure 2 is found in the overview, Figure 1 is found in the 0V Folder. The Raw time domain data used in extracting Figures 3 4 and 5 can be found in the "Raw THz Data" Zip archive.] 5. METHODS ---------- [ The THz time domain spectroscopy measurements were undertaken at 4 K in a continuous flow He cryostat. The sample to be measured, along with a bare sapphire reference, were then mounted co-axially on the cold finger of the cryostat, which was subsequently evacuated and cooled to the required temperature. The time-domain signal was then acquired using 20 fs pulses from a Ti-Sapphire laser, a delay stage and two LT-GaAs-on quartz photo-conductive antennas, with a spectral range of 0.5 - 4.5 THz. The time-domain data is then trimmed (with a boxcar window) to remove unwanted Fabry-Perot reflections and zero-padded by 5 ps in either direction before a Fourier transform was taken. The complex transmittance, is then defined as the ratio between the complex Fourier transforms of the sample and the reference. Equation 1 within the paper can then be used to find the complex conductivity of the sample. The complex conductivity spectra acquired in this manner can then be fitted to equation 2 within the manuscript to obtain the relevant material parameters. A gate bias is then applied between the NiCr top gate electrode and the sample, and the experiment is repeated to obtain the data seen in the paper. ]