Regensburg 2013 – scientific programme

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TT: Fachverband Tiefe Temperaturen

TT 24: Focused Session: Dirac Fermions in Solid-State Systems (jointly with HL)

TT 24.2: Topical Talk

Tuesday, March 12, 2013, 10:00–10:30, H2

Controlling Quantized Edge Transport in Two-dimensional Topological Insulators — Viktor Krueckl, Sven Essert, and •Klaus Richter — Institut für Theoretische Physik, Universität Regensburg, 93040 Regensburg, Germany

Robustness of edge channels against disorder scattering is an outstanding feature of two-dimensional topological insulators (TIs). Here we consider quantized transport and mesoscopic interference phenomena in HgTe-based TIs, systems where the quantum spin Hall state has first been experimentally observed [1]. On the one hand, we discuss mechanisms to steer the spin orientation, and thereby the charge flow between different edges in TI constrictions that turn out to provide rather robust spin transistor functionality [2]. On the other hand, we study the combined effect of a time-reversal symmetry breaking magnetic field and disorder on transport to explore the limits of topological protection and the competition between reflectionless modes, metallic behavior and Anderson localization. In particular, transport in hybrids composed of normal conducting and TI regions shows peculiar quantization phenomena.

[1] M. König et al., Science 318, 766 (2007);

[2] V. Krueckl, K. Richter, Phys Rev. Lett. 107, 086803 (2011).