Regensburg 2016 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 66: Frontiers of Electronic Structure Theory: Focus on Topology and Transport

O 66.6: Poster

Mittwoch, 9. März 2016, 18:15–20:30, Poster A

The quantum anomalous Hall effect in HgMnTe — •Jan Böttcher, Christoph Kleiner, and Ewelina M. Hankiewicz — Uni Würzburg, Institut für Theoretische Physik und Astrophysik, Germany

Recently, the quantum anomalous Hall (QAH) effect was predicted to exist in Mn doped HgTe. Within the QAH phase only one edge state remains at an edge due to an opposite coupling of spin to the magnetization. The experimental proof is however still outstanding. The paramagnetic nature of the Mn impurities gives rise to the formation of Landau levels which makes it experimentally challenging to distinguish the QAH from a conventional quantum Hall (QH) state. Based on the BHZ model, we present an extended study of the transition from the quantum spin Hall to the QAH state as well as the QAH to the quantum Hall state. For this purpose, we make use of the finite difference method and compare the results with analytical calculations. Hallmarks of the QAH states in the presence of magnetic fields are discussed. The BHZ model has natural limitations in the high magnetic field regime. We therefore compare our results with band structure calculations based on the 8x8 Kane Hamiltonian. Signatures in the magnetoresistance are discussed which might open the door to distinguish the QAH from the QH state in future transport experiments.

We acknowledge financial support by the DFG within SFB 1170 "ToCoTronics".