Berlin 2012 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 9: Transport: Topological Insulators 1 (jointly with TT, MA)

HL 9.5: Talk

Monday, March 26, 2012, 10:30–10:45, H 3010

Interplay of bulk and edge states in transport of topological insulators — •Rolf W. Reinthaler and Ewelina M. Hankiewicz — Faculty of Physics and Astrophysics, University of Würzburg, Würzburg, Germany

We study ballistic transport in two-terminal metal/quantum spin-Hall insulator (QSHI)/metal junctions within the effective four band model (conduction/heavy hole bands) [1, 2]. We show that the conductance signals originating from the bulk and the edge contributions are not additive. While for a long junction the transport is determined by the edge states contribution, for a short junction, the conductance signal is built from both, bulk and edge states, in the ratio which depends on the width of the sample. Further, the conductance for short junctions shows a non-monotonic behavior as a function of the sample lenght in topological insulator regime [3]. Suprisingly this non-monotonic behavior of conductance can be traced to the formation of an effectively propagating solution which is robust against scalar disorder. Our predictions should be experimentally verifiable in HgTe QWs and BiSe thin films.

We acknowledge the financial support of the German DFG Grant HA5893/1-2 .
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