Theoretical Evidence for the Berry-Phase Mechanism of Anomalous Hall Transport: First-principles Studies on CuCr$_2$Se$_{4-x}$Br$_x$

TL;DR

This paper provides first-principles evidence that the Berry-Phase mechanism explains the doping-dependent sign reversal of the anomalous Hall effect in CuCr₂Se₄₋ₓBrₓ, aligning well with experimental data and predicting further sign changes.

Contribution

It demonstrates through systematic calculations that the Berry-Phase mechanism accounts for the observed sign reversal in AHE due to doping in CuCr₂Se₄₋ₓBrₓ, a novel insight into the origin of AHE.

Findings

Doping-dependent sign reversal in AHE explained by Berry-Phase mechanism

Systematic calculations match experimental data across doping range

Predicted further sign change in AHE for future experiments

Abstract

To justify the origin of anomalous Hall effect (AHE), it is highly desirable to have the system parameters tuned continuously. By quantitative calculations, we show that the doping dependent sign reversal in CuCr$_{2}$Se$_{4-x}$Br$_{x}$, observed but not understood, is nothing but direct evidence for the Berry-Phase mechanism of AHE. The systematic calculations well explain the experiment data for the whole doping range where the impurity scattering rates is changed by several orders with Br substitution. Further sign change is also predicted, which may be tested by future experiments.