Sign change in the anomalous Hall effect and strong transport effects in a 2D massive Dirac metal due to spin-charge correlated disorder

Abstract

The anomalous Hall effect (AHE) is highly sensitive to disorder in the metallic phase. Here we show that statistical correlations between the charge and spin disorder sectors strongly affect both the longitudinal conductivity and the sign/magnitude of AHE. Correlations between mass and charge disorder can be absorbed into an effective mass. In general, random gauge fields are also present due to e.g. in-plane component of magnetization in topological insulator, causing an anisotropy in conductivity. As the correlation between the charge and gauge-mass components increases, so does the AHE, achieving its universal value, and even exceed it, although the system is an impure metal. The AHE can change sign when the anti-correlations reverse the effective mass, a possible mechanism behind the sign change seen in recent experiments.