Structural, optical and electronic properties of the wide bandgap topological insulator Bi1.1Sb0.9Te2S

Yu E. Khatchenko; M.V. Yakushev; C. Seibel; H. Bentmann; M. Orlita; V.  Golyashov; Y.S. Ponosov; N.P.  Stepina; A.V. Mudryi; K.A. Kokh; O.E. Tereshchenko; F. Reinert; R.W. Martin; T.V. Kuznetsova

doi:10.1016/j.jallcom.2021.161824

Structural, optical and electronic properties of the wide bandgap topological insulator Bi_1.1Sb_0.9Te₂S

Yu E. Khatchenko, M.V. Yakushev, C. Seibel, H. Bentmann, M. Orlita, V. Golyashov, Y.S. Ponosov, N.P. Stepina, A.V. Mudryi, K.A. Kokh, O.E. Tereshchenko, F. Reinert, R.W. Martin, T.V. Kuznetsova

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Abstract

Successful applications of a topological insulator (TI) in spintronics require its bandgap to be wider then in a typical TI and the energy position of the Dirac point in the dispersion relations to be away from the valence and conduction bands. In this study we grew Bi_1.1Sb_0.9Te₂S crystals and examined their elemental composition, structural, optical and electronic properties as well as the electronic band structure. The high structural quality of the grown crystals was established by X-ray diffraction and Raman spectroscopy. Angular resolved photoelectron spectroscopy demonstrated a near parabolic character of the valence and conduction bands and a direct bandgap of 0.36 eV. The dispersion relations also revealed a Dirac cone, confirming the topological insulator nature of this material, with the position of the Dirac point being 100 meV above the valence band maximum. Far infrared reflectivity spectra revealed a plasma edge and two phonon dips. Fitting these spectra with theoretical functions based on the Drude-Lorentz model allows determination of the high frequency dielectric constant (41.3), plasma frequency (936 cm−1) and the frequencies of two infrared phonons (177.7 cm−1 and 77.4 cm−1).

Original language	English
Article number	161824
Number of pages	22
Journal	Journal of Alloys and Compounds
Volume	890
Early online date	2 Sept 2021
DOIs	https://doi.org/10.1016/j.jallcom.2021.161824
Publication status	Published - 15 Jan 2022

Keywords

topological insulator
Bi1.1Sb0.9Te2S
electronic structure
ARPES
far infrared
optical reflectivity

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10.1016/j.jallcom.2021.161824

Khatchenko-etal-JAC-2021-Structural-optical-and-electronic-properties-of-the-wide-bandgap-topological-insulatorAccepted author manuscript, 674 KBLicence: CC BY-NC-ND 4.0

Nanoanalysis for Advanced Materials and Healthcare - EPSRC strategic equipment
Martin, R. (Principal Investigator), Edwards, P. (Co-investigator), Faulds, K. (Co-investigator), Florence, A. (Co-investigator), Graham, D. (Co-investigator), Sefcik, J. (Co-investigator), Ter Horst, J. (Co-investigator), Trager-Cowan, C. (Co-investigator), Uttamchandani, D. (Co-investigator) & Wark, A. (Co-investigator)
EPSRC (Engineering and Physical Sciences Research Council)
8/11/15 → 7/11/19
Project: Research
University Of Strathclyde - Equipment Account
Gachagan, A. (Principal Investigator), He, W. (Principal Investigator), Jaroszynski, D. (Principal Investigator), Martin, R. (Principal Investigator), McArthur, S. (Principal Investigator), McArthur, S. (Principal Investigator), Connolly, P. (Co-investigator), Edwards, P. (Co-investigator), Faulds, K. (Co-investigator), Florence, A. (Co-investigator), Graham, D. (Co-investigator), Leithead, B. (Co-investigator), Sefcik, J. (Co-investigator), Ter Horst, J. (Co-investigator), Trager-Cowan, C. (Co-investigator), Uttamchandani, D. (Co-investigator) & Wark, A. (Co-investigator)
EPSRC (Engineering and Physical Sciences Research Council)
1/08/13 → 28/02/23
Project: Research

ESEM Quanta 250
Martin, R.
Physics
Facility/equipment: Equipment

Cite this

Khatchenko, Y. E., Yakushev, M. V., Seibel, C., Bentmann, H., Orlita, M., Golyashov, V., Ponosov, Y. S., Stepina, N. P., Mudryi, A. V., Kokh, K. A., Tereshchenko, O. E., Reinert, F., Martin, R. W., & Kuznetsova, T. V. (2022). Structural, optical and electronic properties of the wide bandgap topological insulator Bi_1.1Sb_0.9Te₂S. Journal of Alloys and Compounds, 890, Article 161824. https://doi.org/10.1016/j.jallcom.2021.161824

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title = "Structural, optical and electronic properties of the wide bandgap topological insulator Bi1.1Sb0.9Te2S",

abstract = "Successful applications of a topological insulator (TI) in spintronics require its bandgap to be wider then in a typical TI and the energy position of the Dirac point in the dispersion relations to be away from the valence and conduction bands. In this study we grew Bi1.1Sb0.9Te2S crystals and examined their elemental composition, structural, optical and electronic properties as well as the electronic band structure. The high structural quality of the grown crystals was established by X-ray diffraction and Raman spectroscopy. Angular resolved photoelectron spectroscopy demonstrated a near parabolic character of the valence and conduction bands and a direct bandgap of 0.36 eV. The dispersion relations also revealed a Dirac cone, confirming the topological insulator nature of this material, with the position of the Dirac point being 100 meV above the valence band maximum. Far infrared reflectivity spectra revealed a plasma edge and two phonon dips. Fitting these spectra with theoretical functions based on the Drude-Lorentz model allows determination of the high frequency dielectric constant (41.3), plasma frequency (936 cm−1) and the frequencies of two infrared phonons (177.7 cm−1 and 77.4 cm−1).",

keywords = "topological insulator, Bi1.1Sb0.9Te2S, electronic structure, ARPES, far infrared, optical reflectivity",

author = "Khatchenko, {Yu E.} and M.V. Yakushev and C. Seibel and H. Bentmann and M. Orlita and V. Golyashov and Y.S. Ponosov and N.P. Stepina and A.V. Mudryi and K.A. Kokh and O.E. Tereshchenko and F. Reinert and R.W. Martin and T.V. Kuznetsova",

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doi = "10.1016/j.jallcom.2021.161824",

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Khatchenko, YE, Yakushev, MV, Seibel, C, Bentmann, H, Orlita, M, Golyashov, V, Ponosov, YS, Stepina, NP, Mudryi, AV, Kokh, KA, Tereshchenko, OE, Reinert, F, Martin, RW & Kuznetsova, TV 2022, 'Structural, optical and electronic properties of the wide bandgap topological insulator Bi_1.1Sb_0.9Te₂S', Journal of Alloys and Compounds, vol. 890, 161824. https://doi.org/10.1016/j.jallcom.2021.161824

TY - JOUR

T1 - Structural, optical and electronic properties of the wide bandgap topological insulator Bi1.1Sb0.9Te2S

AU - Khatchenko, Yu E.

AU - Yakushev, M.V.

AU - Seibel, C.

AU - Bentmann, H.

AU - Orlita, M.

AU - Golyashov, V.

AU - Ponosov, Y.S.

AU - Stepina, N.P.

AU - Mudryi, A.V.

AU - Kokh, K.A.

AU - Tereshchenko, O.E.

AU - Reinert, F.

AU - Martin, R.W.

AU - Kuznetsova, T.V.

PY - 2022/1/15

Y1 - 2022/1/15

N2 - Successful applications of a topological insulator (TI) in spintronics require its bandgap to be wider then in a typical TI and the energy position of the Dirac point in the dispersion relations to be away from the valence and conduction bands. In this study we grew Bi1.1Sb0.9Te2S crystals and examined their elemental composition, structural, optical and electronic properties as well as the electronic band structure. The high structural quality of the grown crystals was established by X-ray diffraction and Raman spectroscopy. Angular resolved photoelectron spectroscopy demonstrated a near parabolic character of the valence and conduction bands and a direct bandgap of 0.36 eV. The dispersion relations also revealed a Dirac cone, confirming the topological insulator nature of this material, with the position of the Dirac point being 100 meV above the valence band maximum. Far infrared reflectivity spectra revealed a plasma edge and two phonon dips. Fitting these spectra with theoretical functions based on the Drude-Lorentz model allows determination of the high frequency dielectric constant (41.3), plasma frequency (936 cm−1) and the frequencies of two infrared phonons (177.7 cm−1 and 77.4 cm−1).

AB - Successful applications of a topological insulator (TI) in spintronics require its bandgap to be wider then in a typical TI and the energy position of the Dirac point in the dispersion relations to be away from the valence and conduction bands. In this study we grew Bi1.1Sb0.9Te2S crystals and examined their elemental composition, structural, optical and electronic properties as well as the electronic band structure. The high structural quality of the grown crystals was established by X-ray diffraction and Raman spectroscopy. Angular resolved photoelectron spectroscopy demonstrated a near parabolic character of the valence and conduction bands and a direct bandgap of 0.36 eV. The dispersion relations also revealed a Dirac cone, confirming the topological insulator nature of this material, with the position of the Dirac point being 100 meV above the valence band maximum. Far infrared reflectivity spectra revealed a plasma edge and two phonon dips. Fitting these spectra with theoretical functions based on the Drude-Lorentz model allows determination of the high frequency dielectric constant (41.3), plasma frequency (936 cm−1) and the frequencies of two infrared phonons (177.7 cm−1 and 77.4 cm−1).

KW - topological insulator

KW - Bi1.1Sb0.9Te2S

KW - electronic structure

KW - ARPES

KW - far infrared

KW - optical reflectivity

U2 - 10.1016/j.jallcom.2021.161824

DO - 10.1016/j.jallcom.2021.161824

M3 - Article

SN - 0925-8388

VL - 890

JO - Journal of Alloys and Compounds

JF - Journal of Alloys and Compounds

M1 - 161824

ER -

Structural, optical and electronic properties of the wide bandgap topological insulator Bi1.1Sb0.9Te2S

Abstract

Keywords

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Nanoanalysis for Advanced Materials and Healthcare - EPSRC strategic equipment

University Of Strathclyde - Equipment Account

Equipment

ESEM Quanta 250

Cite this

Structural, optical and electronic properties of the wide bandgap topological insulator Bi_1.1Sb_0.9Te₂S