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

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.