Topological Insulators at Room Temperature

Haijun Zhang; Chao-Xing Liu; Xiao-Liang Qi; Xi Dai; Zhong Fang; Shou-Cheng Zhang

paper

Topological Insulators at Room Temperature

arXiv:0812.1622

Abstract

Topological insulators are new states of quantum matter with surface states protected by the time-reversal symmetry. In this work, we perform first-principle electronic structure calculations for $S b_{2} T e_{3}$ , $S b_{2} S e_{3}$ , $B i_{2} T e_{3}$ and $B i_{2} S e_{3}$ crystals. Our calculations predict that $S b_{2} T e_{3}$ , $B i_{2} T e_{3}$ and $B i_{2} S e_{3}$ are topological insulators, while $S b_{2} S e_{3}$ is not. In particular, $B i_{2} S e_{3}$ has a topologically non-trivial energy gap of $0.3 e V$ , suitable for room temperature applications. We present a simple and unified continuum model which captures the salient topological features of this class of materials. These topological insulators have robust surface states consisting of a single Dirac cone at the $Γ$ point.

5 pages, 4 figures