Spin-orbit coupling effect in (Ga,Mn)As films: anisotropic exchange interactions and magnetocrystalline anisotropy

TL;DR

This paper investigates the spin-orbit coupling effects in (Ga,Mn)As films, focusing on how anisotropic exchange interactions and surface effects influence magnetocrystalline anisotropy through ab-initio calculations.

Contribution

It provides a detailed ab-initio analysis of the origins of magnetocrystalline anisotropy and exchange anisotropy in (Ga,Mn)As films, highlighting surface and lattice distortion effects.

Findings

Surface regions significantly contribute to in-plane uniaxial anisotropy.

Exchange anisotropy is influenced by tetragonal distortion and surface/interface effects.

Ab-initio calculations quantify the role of spin-orbit coupling in magnetic anisotropy.

Abstract

The magneto-crystalline anisotropy (MCA) of (Ga,Mn)As films has been studied on the basis of ab-initio electronic structure theory by performing magnetic torque calculations. An appreciable contribution to the in-plane uniaxial anisotropy can be attributed to an extended region adjacent to the surface. Calculations of the exchange tensor allow to ascribe a significant part to the MCA to the exchange anisotropy, caused either by a tetragonal distortion of the lattice or by the presence of the surface or interface.