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HL: Fachverband Halbleiterphysik

HL 17: Transport: Topological Insulators - 2D (Joint session of DS, HL, MA, O and TT, organized by TT)

HL 17.11: Vortrag

Montag, 7. März 2016, 17:45–18:00, H18

Anisotropic magnetoresistance from the surface states of disordered topological insulators — •Henry Legg and Achim Rosch — Institut für Theoretische Physik, Universität zu Köln, D-50937 Cologne, Germany

In the presence of time-reversal symmetry electrons on the surface of a topological insulator cannot backscatter from disorder. A magnetic field parallel to the surface lifts this protection mechanism and enables backscattering which is predominantly in the direction parallel to the magnetic field. As a result the anisotropy of magentoresistance parallel and perpendicular to B is a sensitive probe of the loss of topological protection when time-reversal symmetry is broken.

Using a self-consistent T-matrix approximation we demonstrate how an in-plane magnetic field dramatically alters both the density of states and the resistivity of a topological insulator’s surface. Our results are compared to experiments where the strong dependence on gate voltages provides an especially clear experimental signature of the scattering mechanism.