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

JOURNAL OF ALLOYS AND COMPOUNDS

卷:890

Article

Khatchenko, Yu E.¹  Yakushev, M., V^1,2,3  Seibel, C.^4,5  Bentmann, H.^4,5  Orlita, M.⁶  Golyashov, V⁷  Ponosov, Y. S.^1,3  Stepina, N. P.⁷  Mudriy, A., V⁸  Kokh, K. A.^9,10,11  Tereshchenko, O. E.^7,11  Reinert, F.^4,5  Martin, R. W.¹²  Kuznetsova, T., V^1,3 

[1] UB RAS, MN Miheev Inst Met Phys, 18 S Kovalevskaya Str, Ekaterinburg 620108, Russia

[2] UB RAS, Inst Solid State Chem, Ekaterinburg 620990, Russia

[3] Ural Fed Univ, 19 Mira Str, Ekaterinburg 620002, Russia

[4] Univ Wurzburg, Experimentelle Phys 7, D-97074 Wurzburg, Germany

[5] Univ Wurzburg, Wurzburg Dresden Cluster Excellence Ct Qmat, D-97074 Wurzburg, Germany

[6] LNCMI, 25 Martyrs Ave,BP 166, F-38042 Grenoble 9, France

[7] SB RAS, Rzhanov Inst Semicond Phys, 13 Ac Lavrentieva Ave, Novosibirsk 630090, Russia

[8] NASB, Sci Pract Mat Res Ctr, 19 P Brovki Str, Minsk 220072, BELARUS

[9] SB RAS, VS Sobolev Inst Geol & Mineral, 3 Koptyuga Ave, Novosibirsk 630090, Russia

[10] Kemerovo State Univ, 6 Krasnaya Str, Kemerovo 650000, Russia

[11] Novosibirsk State Univ, 1 Pirogova Str, Novosibirsk 630090, Russia

[12] Strathclyde Univ, Dept Phys, SUPA, 107 Rottenrow, Glasgow G4 0NG, Lanark, Scotland

关键词: Topological insulator;    Bi1.1Sb0.9Te2S;    Electronic structure;    ARPES;    Far infrared;    Optical reflectivity;   

DOI  :  10.1016/j.jallcom.2021.161824

来源: Elsevier

【 摘 要 】

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)). (C) 2021 Elsevier B.V. All rights reserved.

【 授权许可】

Free