Berlin 2012 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 28: Focus Session: Topological Insulators (jointly with MA, TT)

HL 28.2: Talk

Tuesday, March 27, 2012, 09:45–10:00, ER 164

Topological surface states in a strained three-dimensional HgTe — •Elena G. Novik¹, Chaoxing Liu¹, Christoph Brüne¹, Ewelina M. Hankiewicz², Hartmut Buhmann¹, Shoucheng Zhang³, and Laurens W. Molenkamp¹ — ¹Physikalisches Institut (EP3), University of Würzburg, 97074 Würzburg — ²Institut für Theoretische Physik und Astrophysik, University of Würzburg, 97074 Würzburg — ³Department of Physics, McCullough Building, Stanford University, Stanford, California 94305-4045, USA

Three-dimensional (3D) HgTe is a semimetal which is charge-neutral when the Fermi energy is at the touching point between the light-hole and heavy-hole Γ8 bands at the Brillouin zone center. With applied strain a gap of about 20 meV opens up between the light-hole and heavy-hole bands, so that strained 3D HgTe is expected to be a 3D topological insulator with Dirac-like surface states [1]. In most of 3D topological insulators the observation of surface charge transport is obscured by the bulk conductivity. The voltage applied to the gate on top of the HgTe structure allows the suppression of the bulk transport contribution, thus only the surface electrons can be accessed in transport when the Fermi energy is shifted into the gap. The self-consistent calculations of the band structure and density of states for a strained HgTe layer have been done for different values of the gate voltage.

[1] C. Brüne et al. Phys. Rev. Lett. 106, 126803 (2011).