New Journal of Physics (Jan 2015)

Response of the topological surface state to surface disorder in TlBiSe2

  • Florian Pielmeier,
  • Gabriel Landolt,
  • Bartosz Slomski,
  • Stefan Muff,
  • Julian Berwanger,
  • Andreas Eich,
  • Alexander A Khajetoorians,
  • Jens Wiebe,
  • Ziya S Aliev,
  • Mahammad B Babanly,
  • Roland Wiesendanger,
  • Jürg Osterwalder,
  • Evgueni V Chulkov,
  • Franz J Giessibl,
  • J Hugo Dil

DOI
https://doi.org/10.1088/1367-2630/17/2/023067
Journal volume & issue
Vol. 17, no. 2
p. 023067

Abstract

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Through a combination of experimental techniques we show that the topmost layer of the topological insulator TlBiSe _2 as prepared by cleavage is formed by irregularly shaped Tl islands at cryogenic temperatures and by mobile Tl atoms at room temperature. No trivial surface states are observed in photoemission at low temperatures, which suggests that these islands cannot be regarded as a clear surface termination. The topological surface state is, however, clearly resolved in photoemission experiments. This is interpreted as direct evidence of its topological self-protection and shows the robust nature of the Dirac cone-like surface state. Our results can also help explain the apparent mass acquisition in S-doped TlBiSe _2 .

Keywords