Direct Evidence for the Dirac-Cone Topological Surface States in Ternary Chalcogenide TlBiSe2

Takafumi Sato; Kouji Segawa; Hua Guo; Katsuaki Sugawara; Seigo Souma; Takashi Takahashi; Yoichi Ando

doi:10.1103/PhysRevLett.105.136802

Direct Evidence for the Dirac-Cone Topological Surface States in Ternary Chalcogenide TlBiSe2

Mesoscale and Nanoscale Physics 2010-12-21 v2 Strongly Correlated Electrons

Authors: Takafumi Sato , Kouji Segawa , Hua Guo , Katsuaki Sugawara , Seigo Souma , Takashi Takahashi , Yoichi Ando

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Abstract

We have performed high-resolution angle-resolved photoemission spectroscopy on TlBiSe2, which is a member of the ternary chalcogenides theoretically proposed as candidates for a new class of three-dimensional topological insulators. By measuring the energy band dispersions over the entire surface Brillouin zone, we found a direct evidence for a non-trivial surface metallic state showing a X-shaped energy dispersion within the bulk band gap. The present result unambiguously establishes that TlBiSe2 is a strong topological insulator with a single Dirac cone at the Brillouin-zone center. The observed bulk band gap of 0.4 eV is the largest among known topological insulators, making TlBiSe2 the most promising material for studying room-temperature topological phenomena.

Keywords

topological insulator Dirac cone surface states angle-resolved photoemission spectroscopy TlBiSe2 ternary chalcogenide

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@article{arxiv.1006.2437,
  title  = {Direct Evidence for the Dirac-Cone Topological Surface States in Ternary Chalcogenide TlBiSe2},
  author = {Takafumi Sato and Kouji Segawa and Hua Guo and Katsuaki Sugawara and Seigo Souma and Takashi Takahashi and Yoichi Ando},
  journal= {arXiv preprint arXiv:1006.2437},
  year   = {2010}
}

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4 pages, 4 figures

Direct Evidence for the Dirac-Cone Topological Surface States in Ternary Chalcogenide TlBiSe2

Abstract

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