Berlin 2012 – scientific programme

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O: Fachverband Oberflächenphysik

O 37: [MA] Joint Session "Topological Insulators II" (jointly with DS, HL, O, TT)

O 37.10: Talk

Wednesday, March 28, 2012, 12:00–12:15, EB 301

Prediction of topological insulators in TlBiSe2 family of chalcogenides — •binghai yan — BCCMS, University of Bremen, Bremen

In this work, we predicted several new topological insulator materials in thallium (Tl) based ternary chalcogenides from first-principles calculations, including TlBiQ2 and TlSbQ2 (Q=Te, Se and S). TlBiSe2 and TlSbSe2 are found to be strong TIs with a large energy gap (~ 0.2 eV), while TlBiTe2 is a topological semimetal. A simple Dirac-type dispersion of topological surface states is observed, similar to the Bi2Se3 type of materials. On the other hand, TlBiS2, TlSbTe2 and TlSbS2 are small gap insulators near the topological trivial-nontrivial transition boundary. Particularly TlBiTe2 can be a good candidate in the seeking of Majorana fermions for its co-existing superconductivity property. The topological feature of TlBiSe2 and TlBiTe2 has already been confirmed by recent experiments. References: 1. B.H. Yan, C.X. Liu, H.J. Zhang, C.Y. Yam, X.L. Qi, Th. Frauenheim and S.C. Zhang, Europhys. Lett. 90, 37002 (2010). 2. Y. L. Chen, Z. K. Liu, J. G. Analytis, J.-H. Chu, H. J. Zhang, B. H. Yan, S.-K. Mo, R. G. Moore, D. H. Lu, I. R. Fisher, S. C. Zhang, Z. Hussain, and Z.-X. Shen, Phys. Rev. Lett. 105, 266401(2011).