Influence of non-local exchange on RKKY interactions in III-V diluted magnetic semiconductors

TL;DR

This paper investigates how non-local exchange interactions influence the anisotropic RKKY interactions in III-V diluted magnetic semiconductors, highlighting the roles of band structure and spin-orbit coupling in magnetic properties.

Contribution

It introduces a semi-phenomenological tight-binding model that incorporates non-local exchange effects to analyze RKKY interactions in GaAs-based magnetic semiconductors.

Findings

Non-local exchange significantly affects RKKY anisotropy.

Spin-orbit coupling influences magnetic interaction strength.

Results estimate magnetization suppression due to frustration.

Abstract

The RKKY interaction between substitutional Mn local moments in GaAs is both spin-direction-dependent and spatially anisotropic. In this Letter we address the strength of these anisotropies using a semi-phenomenological tight-binding model which treats the hybridization between Mn d-orbitals and As p-orbitals perturbatively and accounts realistically for the non-local exchange interaction between their spins. We show that exchange non-locality, valence-band spin-orbit coupling, and band-structure anisotropy all play a role in determining the strength of both effects. We use these results to estimate the degree of ground-state magnetization suppression due to frustrating interactions between randomly located Mn ions.