Electronic and spin structure of the wide-band-gap topological insulator: Nearly stoichiometricBi2Te2S

E V Chulkov,H Iwasawa,K A Kokh,T Okuda,O E Tereshchenko,M Natamane,K Shimada,V A Golyashov,E F Schwier,M Taniguchi,S V Eremeev,I P Rusinov,A Kimura,E Annese

doi:10.1103/physrevb.97.205113

Abstract

We acknowledge partial support from the Saint Petersburg State University (Grant No. 15.61.202.2015), Tomsk State University competitiveness improvement program (Project No. 8.1.01.2017), and the Spanish Ministry of Science and Innovation (Grant No. FIS2016-75862-P). This study was partially supported by the Russian Science Foundation (Projects No. 17-12-01047, for the electrophysical properties, and No. 18-12-00169, for the theoretical calculations) and by the Russian Foundation for Basic Research (Project No. 17-08-00955, for the crystal growth and structural characterization). S.V.E. acknowledges support by the Fundamental Research Program of the State Academies of Sciences for 2013–2020. I.P.R. acknowledges support by the Ministry of Education and Science of the Russian Federation within the framework of the governmental program Megagrants (state task No. 3.8895.2017/P220). A.K. was financially supported by KAKENHI Grants No. 26247064 and No. 17H06138.

Highlights

IntroductionThe binary tetradymitelike Bi chalcogenides Bi2Se3 and Bi2Te3 are widely regarded as model examples of the threedimensional topological insulators since they host a single metallic Dirac state [1,2,3,4,5,6,7]
Topological insulators (TIs) are characterized by an insulating energy gap in the bulk and the gapless spin-polarized metallic surface states with linear Dirac conelike dispersion in the energy-momentum space with helical spin textures protected by time-reversal symmetry, which can favor the quantum spin transport without heat dissipation [1,2].The binary tetradymitelike Bi chalcogenides Bi2Se3 and Bi2Te3 are widely regarded as model examples of the threedimensional topological insulators since they host a single metallic Dirac state [1,2,3,4,5,6,7]
We show that the surface electronic spectrum of this compound is characterized by the topological surface state (TSS), which Dirac point is located above the valence band and Fermi level

Summary

Introduction

The binary tetradymitelike Bi chalcogenides Bi2Se3 and Bi2Te3 are widely regarded as model examples of the threedimensional topological insulators since they host a single metallic Dirac state [1,2,3,4,5,6,7] These compounds are not insulators, but have metallic bulk conductivity as a consequence of unintentional doping by defects: the Se vacancies in Bi2Se3 and Bi-Te antisite defects in Bi2Te3 [4,5,8]. The isolation of the surface states from the bulk electronic states and the Fermi level (EF ) located in the bulk band gap is the minimal requirement for the quantum spin transport. To this end, various experimental efforts exploited the tune of EF with doping [7,9]. One of the strategies to control the native defects in Teand Se-containing TIs is using ternary Bi-Te-Se alloy systems

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Results

Conclusion