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HL: Fachverband Halbleiterphysik

HL 59: Topological insulators: Theory (with MA/O/TT)

HL 59.5: Vortrag

Mittwoch, 2. April 2014, 10:30–10:45, POT 151

Natural three-dimensional topological insulators in Tl₄PbTe₃ and Tl₄SnTe₃ — •Chengwang Niu^1,2, Ying Dai¹, Baibiao Huang¹, Gustav Bihlmayer², Yuriy Mokrousov², Daniel Wortmann², and Stefan Blügel² — ¹School of Physics, Shandong University, Jinan, China — ²Peter Grünberg Institut (PGI-1) & Institute for Advanced Simulation (IAS-1), Forschungszentrum Jülich and JARA, 52425 Jülich, Germany

The recently discovered three-dimensional topological insulators have attracted much interest due to their exceptional properties of possessing insulating bulk but time-reversal symmetry protected metallic surfaces with Dirac-like band structure [1,2]. The search for new topological insulators is critical for both fundamental and practical interests. Based on first-principles calculations, we reveal that both Tl₄PbTe₃ and Tl₄SnTe₃ are strong topological insulators with different band inversion behaviors at Γ point [3]. The mechanisms of band inversion in Tl₄PbTe₃ and Tl₄SnTe₃, as well as in Bi₂Se₃ and Sb₂Se₃, are investigated and classified. The Z₂ topological invariants and topological surface states are investigated to confirm the topologically non-trivial phase. Our calculations further indicate that the electron- or hole-type Dirac fermion can be effectively engineered by hole doping, which is necessary for device applications of topological insulators.

[1] M. Hasan and C. Kane, Rev. Mod. Phys. 82, 3045 (2010).

[2] X.-L. Qi and S.-C. Zhang, Rev. Mod. Phys. 83, 1057 (2011).

[3] C. Niu et al., in preparation.