URhGe -- Altermagnetic Ferromagnet

TL;DR

This paper investigates the altermagnetic ferromagnet URhGe, revealing that its crystal symmetry, specifically non-symmorphic symmetry, results in zero Berry curvature, contrary to typical ferromagnets where Berry curvature influences the anomalous Hall effect.

Contribution

The study demonstrates that URhGe's non-symmorphic crystal symmetry leads to zero Berry curvature, providing insight into its unique electronic and magnetic properties.

Findings

Berry curvature is zero in URhGe due to non-symmorphic symmetry.

URhGe's anomalous Hall effect is not influenced by Berry curvature.

Crystal symmetry explains the absence of Berry curvature in this material.

Abstract

It is well known that the anomalous Hall effect in ferromagnetic and strongly paramagnetic metals in addition to electron skew scattering on impurities is determined by internal mechanism linked to the Berry curvature, a quantum-mechanical property of the electron states of a perfect crystal. Experimentally, however, it has been established that the Berry curvature does not play any role in the Hall resistance of the ferromagnet URhGe. URhGe is so called altermagnetic ferromagnet which crystal symmetry includes operation of time inversion only in combination with rotations and reflections. The explanation for strictly zero Berry curvature of electronic states in this material lies in the non-symmorphic symmetry of its crystal lattice.