Giant Crystal Hall Effect in Collinear Antiferromagnetic $\gamma$-FeMn

TL;DR

This paper predicts a giant crystal Hall effect in antiferromagnetic $ ext{FeMn}$ that cannot be explained by traditional mechanisms, revealing a universal phenomenon linked to symmetry and Fermi surface properties.

Contribution

It introduces the concept of a giant crystal Hall effect in antiferromagnetic $ ext{FeMn}$, driven by asymmetric Fermi surface velocities, and shows its universality beyond specific materials.

Findings

Hall angle up to 18.4% at low temperature

CHE origin linked to asymmetric group velocities on Fermi surface

Effect is universal in crystals with similar symmetry, independent of local magnetization

Abstract

The spontaneous Hall effect is usually governed by three conventional mechanisms, such as the Berry curvature, skew scattering and side jump, which widely exist in ferromagnetic or antiferromagnetic materials. However, in this work, based on first principle calculations, we predict a giant crystal Hall effect (CHE) in the antiferromagnetic $\gamma$-FeMn, which can not be understood by the previous three conventional mechanisms and the Hall angle therein can be as large as 18.4% at low temperature. Furthermore, with Boltzmann transport equation and a tight-binding model, we conclude that, the asymmetric group velocities on Fermi surface is the origin of this CHE in $\gamma$-FeMn. And with a systematic symmetry argument, we show that, this unusual effect is not dependent on specific materials but universal in any crystals with similar symmetry even without local magnetization.