Volume 90, Number 3, May 2010
|Number of page(s)||5|
|Section||Condensed Matter: Electronic Structure, Electrical, Magnetic and Optical Properties|
|Published online||01 June 2010|
Theoretical prediction of topological insulators in thallium-based III-V-VI2 ternary chalcogenides
Bremen Center for Computational Materials Science, Universität Bremen - Am Fallturm 1, 28359 Bremen, Germany, EU
2 Physikalisches Institut (EP3) and Institute for Theoretical Physics and Astrophysics, University of Würzburg 97074 Würzburg, Germany, EU
3 Beijing National Laboratory for Condensed Matter Physics, and Institute of Physics, Chinese Academy of Sciences Beijing 100190, China
4 Department of Physics, McCullough Building, Stanford University - Stanford, CA 94305-4045, USA
5 Microsoft Research, Station Q, Elings Hall, University of California - Santa Barbara, CA 93106, USA
Accepted: 26 April 2010
We predict a new class of three-dimensional topological insulators in thallium-based III-V-VI2 ternary chalcogenides, including lBiQ2 and TlSbQ2 (Q = Te, Se and S). These topological insulators have robust and simple surface states consisting of a single Dirac cone at the Γ point. The mechanism for topological insulating behavior is elucidated using both first-principle calculations and effective field theory models. Remarkably, one topological insulator in this class, TlBiTe2, is also a superconductor when doped with p-type carriers. We discuss the possibility that this material could be a topological superconductor. Another material, TlSbS2, is on the border between topological insulator and trivial insulator phases, in which a topological phase transition can be driven by pressure.
PACS: 71.20.Nr – Semiconductor compounds / 73.43.-f – Quantum Hall effects / 74.25.-q – Properties of superconductors
© EPLA, 2010
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