Berlin 2015 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 28: Transport: Topological insulators 2 (TT with HL/DS)

HL 28.11: Talk

Tuesday, March 17, 2015, 12:30–12:45, H 3005

How dephasing and charge puddles affect the edge transport in 2d-topological insulators — •Sven Essert, Viktor Krueckl, and Klaus Richter — Institut für Theoretische Physik, Universität Regensburg, 93040 Regensburg, Germany

State of the art 2d-TI material systems show a length dependent non-quantized conductance for sample sizes larger than one micron. This feature is so far not well understood: Coherent elastic backscattering is symmetry forbidden and the observed weak temperature dependence does not seem to match the predictions for inelastic backscattering. We analytically and numerically investigate the effects of a third mechanism which was proposed to play a major role for the edge resistance: The combined effect of dephasing and elastic backscattering in charge puddles which are known to exist in the experimental samples.

We extract a range of dephasing times which are consistent with the experimental results. In addition, we make predictions for experiments on artificial charge puddles from which the real dephasing time scale could be determined.