Berry-phase effects and electronic dynamics in noncollinear antiferromagnetic texture

TL;DR

This paper investigates how noncollinear antiferromagnetic textures influence electron dynamics through Berry-phase effects, revealing emergent gauge fields and potential topological spin Hall effects in metallic AFMs.

Contribution

It introduces a theoretical framework for adiabatic electron dynamics in noncollinear AFMs, highlighting non-Abelian gauge potentials and their effects on electron spin and orbital motion.

Findings

Emergent electric and magnetic fields from AFM textures affect electron spin and orbitals.

Potential for topological spin Hall effect near AFM solitons.

Electron spin rotation occurs when traveling through AFM domain walls.

Abstract

Antiferromagnets (AFMs), in contrast to ferromagnets, show a nontrivial magnetic structure with zero net magnetization. However, they share a number of spintronic effects with ferromagnets, including spin-pumping and spin transfer torques. Both phenomena stem from the coupled dynamics of free carriers and localized magnetic moments. In the present paper I study the adiabatic dynamics of a spin-polarized electrons in a metallic AFM exhibiting a noncollinear 120$^\circ$ magnetic structure. I show that the slowly varying AFM spin texture produces a non-Abelian gauge potential related to the time/space gradients of the N\'{e}el vectors. Corresponding emergent electric and magnetic fields induce rotation of spin and influence the orbital dynamics of free electrons. I discuss both the possibility of a topological spin Hall effect in the vicinity of topological AFM solitons with nonzero curvature and rotation of the electron spin traveling through the AFM domain wall.