Spin and electronic structure of the topological insulator Bi1.5Sb0.5Te1.8Se1.2

Research output: Contribution to journalArticle

Abstract

Electronic and spin structure of the Dirac-cone-like topological surface and valence band states were studied experimentally and theoretically for topological insulator with fractional stoichiometry Bi1.5Sb0.5Te1.8Se1.2 which is considered as one of the best candidates for efficient spin-polarized current generation. By means of spin- and angle-resolved photoelectron spectroscopy we demonstrate the separation of the Dirac point from the bulk states and the helical spin structure of the Dirac cone. For the freshly cleaved surface the Fermi level is located in the bulk band gap and an exposure in residual gases shifts the Fermi level towards the bulk conduction band. Results of the theoretical calculations are in a good agreement with the experimental data. Surface morphology study shows a well-structured atomically sharp surface after cleavage. The transport measurements confirm that this topological insulator has relatively high resistance with semiconductor-like temperature dependence at low temperatures. The studied Bi1.5Sb0.5Te1.8Se1.2 crystals demonstrated a quite large Seebeck coefficient values reaching −400 μV/K at room temperature.

Details

Authors
  • M. V. Filianina
  • I. I. Klimovskikh
  • I. A. Shvets
  • A. G. Rybkin
  • A. E. Petukhov
  • E. V. Chulkov
  • V. A. Golyashov
  • K. A. Kokh
  • O. E. Tereshchenko
  • C. Polley
  • T. Balasubramanian
  • M. Leandersson
  • A. M. Shikin
Organisations
External organisations
  • Saint Petersburg State University
  • Tomsk State University
  • V.S. Sobolev Institute of Geology and Mineralogy
  • Donostia International Physics Center (DIPC)
  • CSIC Centro de Física de Materiales (UPV/EHU)
  • Institute of Semiconductor Physics, Siberian Branch, Russian Academy of Sciences
  • Novosibirsk State University
Research areas and keywords

Subject classification (UKÄ) – MANDATORY

  • Materials Chemistry

Keywords

  • ARPES, Electronic structure, Topological insulators
Original languageEnglish
Pages (from-to)253-258
Number of pages6
JournalMaterials Chemistry and Physics
Volume207
Publication statusPublished - 2018 Mar 1
Publication categoryResearch
Peer-reviewedYes