Chern number spins of Mn acceptor magnets in GaAs

TL;DR

This paper investigates the topological properties of Mn acceptor states in GaAs, revealing how their total spin varies with position and orientation, which impacts their quantum spin dynamics.

Contribution

It introduces a method to determine the effective total spin of Mn acceptor states using magnetic Chern numbers, highlighting the influence of local environment on spin states.

Findings

Total spin changes from J=1 to J=2 near the surface.

Mn pair orientation affects total spin in bulk GaAs.

Berry curvature variations influence spin dynamics.

Abstract

We determine the effective total spin $J$ of local moments formed from acceptor states bound to Mn ions in GaAs by evaluating their magnetic Chern numbers. We find that when individual Mn atoms are close to the sample surface, the total spin changes from $J = 1$ to $J = 2$, due to quenching of the acceptor orbital moment. For Mn pairs in bulk, the total $J$ depends on the pair orientation in the GaAs lattice and on the separation between the Mn atoms. We point out that Berry curvature variation as a function of local moment orientation can profoundly influence the quantum spin dynamics of these magnetic entities.