Anomalous quantum Hall effect induced by disorder in topological insulators

Abstract:

We investigate a transition between a two-dimensional topological insulator conduction state, characterized by a conductance G=2 (in fundamental units e2/h) and a Chern insulator with G=1, induced by polarized magnetic impurities. Two kinds of coupling, ferromagnetic and antiferromagnetic, are considered with the electron and hole subbands. We demonstrate that for strong disorder, a phase G=1 exists even for ferromagnetic order, in contrast with the pbkp_rediction of the mean field approximation. This result is supported by direct numerical computations using Landauer transport formula, and by analytical calculations of the chemical potential and mass renormalization as a function of the disorder strength, in the self-consistent Born approximation. The transition is related to the suppression of one of the spin conduction channels, for strong enough disorder, by selective spin scattering and localization.

Año de publicación:

2015

Keywords:

Fuente:

scopus