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TT: Fachverband Tiefe Temperaturen
TT 26: Transport: Topological Insulators 3 (jointly with HL and MA)
TT 26.12: Talk
Wednesday, March 28, 2012, 12:30–12:45, BH 334
Inelastic electron backscattering in a generic helical edge channel — •Thomas L. Schmidt1,2, Stephan Rachel1, Felix von Oppen3, and Leonid I. Glazman1 — 1Department of Physics, Yale University, 217 Prospect Street, New Haven, CT 06520, USA — 2Department of Physics, University of Basel, 4056 Basel, Switzerland — 3Dahlem Center for Complex Quantum Systems and Fachbereich Physik, Freie Universitaet Berlin, 14195 Berlin, Germany
We calculate the low-temperature conductance of a generic one-dimensional helical liquid which exists at the edge of a two-dimensional topological insulator (quantum spin Hall insulator). In a generic case, the Sz spin-symmetry is absent, which opens a possibility of single-particle inelastic electron backscattering. We show that although time-reversal invariance is preserved, inelastic backscattering gives rise to a temperature-dependent deviation from the quantized conductance, δ G ∝ T4. In addition, δ G is sensitive to the position of the Fermi level in the gap of the insulator. We present an effective model for this type of helical liquid and determine its parameters explicitly from numerical solutions of microscopic models for two-dimensional topological insulators in the presence of Rashba spin-orbit coupling.