Article abstract
Nature Physics 5, 438 - 442 (2009)
Published online: 10 May 2009 | doi:10.1038/nphys1270
Subject Categories: Condensed-matter physics | Materials physics
Topological insulators in Bi2Se3, Bi2Te3 and Sb2Te3 with a single Dirac cone on the surface
Haijun Zhang1, Chao-Xing Liu2, Xiao-Liang Qi3, Xi Dai1, Zhong Fang1 & Shou-Cheng Zhang3
Abstract
Topological insulators are new states of quantum matter in which surface states residing in the bulk insulating gap of such systems are protected by time-reversal symmetry. The study of such states was originally inspired by the robustness to scattering of conducting edge states in quantum Hall systems. Recently, such analogies have resulted in the discovery of topologically protected states in two-dimensional and three-dimensional band insulators with large spin–orbit coupling. So far, the only known three-dimensional topological insulator is BixSb1-x, which is an alloy with complex surface states. Here, we present the results of first-principles electronic structure calculations of the layered, stoichiometric crystals Sb2Te3, Sb2Se3, Bi2Te3 and Bi2Se3. Our calculations predict that Sb2Te3, Bi2Te3 and Bi2Se3 are topological insulators, whereas Sb2Se3 is not. These topological insulators have robust and simple surface states consisting of a single Dirac cone at the 
point. In addition, we predict that Bi2Se3 has a topologically non-trivial energy gap of 0.3 eV, which is larger than the energy scale of room temperature. We further present a simple and unified continuum model that captures the salient topological features of this class of materials.
- Beijing National Laboratory for Condensed Matter Physics, and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- Center for Advanced Study, Tsinghua University, Beijing 100084, China
- Department of Physics, McCullough Building, Stanford University, Stanford, California 94305-4045, USA
Correspondence to: Shou-Cheng Zhang3 e-mail: sczhang@stanford.edu
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