Dresden 2014 – scientific programme
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O: Fachverband Oberflächenphysik
O 29: Topological Insulators
O 29.11: Talk
Tuesday, April 1, 2014, 13:00–13:15, GER 38
Quantum phase transitions of a disordered antiferromagnetic topological insulator — •Paul Baireuther1, Jonathan M. Edge1, Ion C. Fulga1, Carlo W.J. Beenakker1, and Jakub Tworzydlo2 — 1Instituut-Lorentz, Universiteit Leiden, P.O. Box 9506, 2300 RA Leiden, The Netherlands — 2University of Warsaw, Hoza 69, 00-681 Warsaw, Poland
We have studied the effect of electrostatic disorder on the conductivity of a three-dimensional antiferromagnetic insulator (a stack of quantum anomalous Hall layers with staggered magnetization). The phase diagram contains regions where the increase of disorder first causes the appearance of surface conduction (via a topological phase transition), followed by the appearance of bulk conduction (via a metal-insulator transition). The conducting surface states are stabilized by an effective time-reversal symmetry that is broken locally by the disorder but restored on long length scales. A simple self-consistent Born approximation reliably locates the boundaries of this socalled "statistical" topological phase.