Berlin 2015 – scientific programme

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TT: Fachverband Tiefe Temperaturen

TT 20: Transport: Topological Insulators 1 (jointly with DS, HL, MA, O)

TT 20.5: Talk

Monday, March 16, 2015, 16:15–16:30, A 053

Rashba spin-orbit coupling at the quantum spin Hall edge — •Florian Geißler, Francois Crepin, and Björn Trauzettel — Universität Würzburg, Institut für Theoretische Physik und Astrophysik, Germany

Not only since the discovery of the quantum spin Hall effect, and up to most recent questions in the context of topological insulating materials, transport through one-dimensional systems is a problem of great importance and interest. In a quantum spin Hall system, electron transport occurs in conducting edge channels, that are spin-filtered with respect to their direction of motion, and was shown to be topologically protected by time-reversal symmetry. We use the helical Luttinger liquid model to study transport in such systems, when the perfect conductance is perturbed. Particularly, we show that a potential source of backscattering is provided by the combination of a Rashba spin-orbit coupling (SOC) impurity and electron-electron interactions, even though time-reversal symmetry remains preserved. Based on both renormalization group and Keldysh calculations, the scaling of the conductance with the external bias is derived at zero temperature. Moreover, we illustrate, that such SOC-impurities may give rise to interesting effects when being present in an interface of a Luttinger liquid connected to a superconductor.