Berlin 2015 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 37: Transport: Topological insulators 3 (TT with HL/DS)

HL 37.1: Vortrag

Dienstag, 17. März 2015, 14:00–14:15, H 0110

Helical Surface States In Strained HgTe — •Jan Boettcher and Ewelina M. Hankiewicz — Universität Würzburg, Faculty for Physics and Astronomy, TP IV

Strained HgTe is a 3D topological insulator with negligible bulk conductivity, where the transport is dominated by the surface states for a wide density range [1]. We analytically show the existence of a topologically protected surface state within the framework of a simplified 6x6 Kane Hamiltonian defined on the half-space. Strained HgTe is different from other 3D TIs due to an additional coupling of the surface states, forming between the light-hole and electron-like (S) bands, to the heavy-hole bands. This coupling causes an avoided crossing between these bands and, therefore, opens a large gap in the surface state spectrum by which the topological protection is not affected. Furthermore, we investigate the spin texture of the surface states. In the presence of an external magnetic field, we study the Landau level spectrum and discuss the experimental signatures which would be a consequence of our model.

We acknowledge grant HA 5893/4-1 within SPP 1666.

[1] Brüne et al., arXiv:1407.6537 (to be published in PRX 2014).