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

作者:Sato Takafumi*; Segawa Kouji; Guo Hua; Sugawara Katsuaki; Souma Seigo; Takahashi Takashi; Ando Yoichi
来源:Physical Review Letters, 2010, 105(13): 136802.
DOI:10.1103/PhysRevLett.105.136802

摘要

We have performed 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. We found direct evidence for a nontrivial surface metallic state showing an "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 0.35 eV is the largest among known topological insulators, making TlBiSe2 the most promising material for studying room-temperature topological phenomena.

  • 出版日期2010-9-23