Suchergebnisse

We have grown the phase-homogeneous ternary compound with composition Bi2Te1.85S1.15 very close to the stoichiometric Bi2Te2S. The measurements performed with spin- and angle-resolved photoelectron spectroscopy as well as density functional theory and GW calculations revealed a wide-band-gap three-dimensional topological insulator phase. The surface electronic spectrum is characterized by the topological surface state (TSS) with Dirac point located above the valence band and Fermi level lying in the band gap. TSS band dispersion and constant energy contour manifest a weak warping effect near the Fermi level along with in-plane and out-of-plane spin polarization along the Γ-K̄ line. We identified four additional states at deeper binding energies with high in-plane spin polarization. ; 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. ; Peer Reviewed