Large anomalous Hall effect driven by non-vanishing Berry curvature in non-collinear antiferromagnetic Mn3Ge

TL;DR

This paper demonstrates that the non-collinear antiferromagnet Mn3Ge exhibits a large anomalous Hall effect driven by Berry curvature, challenging the notion that only ferromagnets can show such effects, and suggests potential for antiferromagnetic spintronics.

Contribution

It reveals that non-collinear antiferromagnetic Mn3Ge exhibits a large anomalous Hall effect due to Berry curvature, a novel finding for antiferromagnets.

Findings

Large anomalous Hall conductivity in Mn3Ge at room temperature

Berry curvature from chiral spin structure causes the effect

Potential for room temperature antiferromagnetic spintronics

Abstract

It is well established that the anomalous Hall effect that a ferromagnet displays scales with its magnetization. Therefore, an antiferromagnet that has no net magnetization should exhibit no anomalous Hall effect. Here we show that the non-collinear triangular antiferromagnet Mn3Ge exhibits a large anomalous Hall effect comparable to that of ferromagnetic metals; the magnitude of the anomalous conductivity is 500 per ohm per cm at 2 K and 50 per ohm per cm at room temperature. The angular dependence of the anomalous Hall effect measurements confirm that the small residual in-plane magnetic moment has no role in the observed effect. Our theoretical calculations demonstrate that the large anomalous Hall effect in Mn3Ge originates from a non-vanishing Berry curvature that arises from the chiral spin structure, and which also results in a large spin Hall effect, comparable to that of platinum. The present results pave the way to realize room temperature antiferromagnetic spintronics and spin Hall effect based data storage devices.