Electron Dynamics in Slowly Varying Antiferromagnetic Texture

TL;DR

This paper develops a non-Abelian gauge theory to describe conduction electron dynamics in antiferromagnetic materials with slowly varying spin textures, revealing spin-dependent orbital behavior and novel gauge field effects.

Contribution

It introduces a non-Abelian gauge framework for AFM electron dynamics, highlighting differences from FM systems and identifying new emergent gauge fields.

Findings

Electron spin does not follow the background texture in AFM, even adiabatically.

Two emergent gauge fields influence the orbital dynamics, including a novel anomalous velocity.

Distinctive spin dynamics are demonstrated through illustrative examples.

Abstract

Effective dynamics of conduction electrons in antiferromagnetic (AFM) materials with slowly varying spin texture is developed via non-Abelian gauge theory. Quite different from the ferromagnetic (FM) case, the spin of a conduction electron does not follow the background texture even in the adiabatic limit due to the accumulation of a SU(2) non-Abelian Berry phase. Correspondingly, it is found that the orbital dynamics becomes spin-dependent and is affected by two emergent gauge fields. While one of them is the non-Abelian generalization of what has been discovered in FM systems, the other leads to an anomalous velocity that has no FM counterpart. Two examples are provided to illustrate the distinctive spin dynamics of a conduction electron.