Regensburg 2013 – scientific programme
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DF: Fachverband Dielektrische Festkörper
DF 12: Poster 1
DF 12.4: Poster
Tuesday, March 12, 2013, 10:30–13:30, Poster D
Ab initio description of topological insulators — •Christian Franz, Michael Czerner, and Christian Heiliger — I. Physikalisches Institut, Justus Liebig University, Giessen, Germany
In this contribution we investigate 3D topological insulators (TI) using ab initio methods. These materials are insulating as bulk material but have a conducting surface state bridging the band gap, which is protected by time reversal symmetry. Prominent examples of 3D-TIs are BiSb alloys and Bi2Se3. In addition to being protected against (non-magnetic) impurities and other perturbations, the spin of these surface states is locked to their momentum. Therefore, backscattering is suppressed for this states, creating a two dimensional electron gas with high mobility. This inspired many proposed application.
We analyze the band structure of TIs. Since the spin-orbit interaction which creates a band inversion is crucial in TIs we will use a fully relativistic description. This is compared to a result without spin-orbit interaction to identify the band inversion. The appearance of the surface state is demonstrated using half-infinite boundary conditions. Alloys are described using the coherent potential approximation. This is the first step towards an ab initio description of transport in TIs.