Extrinsic anomalous Hall effect in altermagnets

TL;DR

This paper investigates the extrinsic anomalous Hall effect in altermagnets, revealing that in some cases it is comparable to the intrinsic effect and depends on specific magnetic interactions and symmetry properties.

Contribution

It demonstrates the significance of extrinsic contributions to the anomalous Hall conductivity in altermagnets, highlighting their dependence on symmetry and spin-orbit coupling effects.

Findings

Extrinsic AHC is comparable to intrinsic AHC in some altermagnetic groups.

Extrinsic contributions are crucial in materials with Dzyaloshinskii-Moriya interactions.

The behavior is linked to the nonanalytic dependence of AHC on spin-orbit coupling.

Abstract

We find the extrinsic anomalous Hall conductivity (AHC) to be comparable to the intrinsic one in roughly half of the altermagnetic spin Laue groups in the limit of large exchange splitting. In materials with a finite Dzyaloshinskii-Moriya type interaction, the extrinsic contribution is essential even in the clean limit. In other altermagnets it is mostly negligible. This peculiar behavior is linked to the nonanalytic dependence of the intrinsic AHC on spin-orbit coupling. Both originate from the lifting of the spin degeneracy along the nodal planes as the weak spin-orbit coupling breaks the nonrelativistic spin symmetry.