Anisotropic magneto-resistance in a GaMnAs-based single impurity tunnel diode: a tight binding approach

TL;DR

This paper investigates the anisotropic magneto-resistance in a GaMnAs-based single impurity tunnel diode using a tight-binding model, revealing significant anisotropies due to spin-orbit coupling and crystal symmetry effects.

Contribution

It introduces an advanced tight-binding approach to estimate tunnel transmission anisotropy caused by a single Mn impurity in GaAs, highlighting the role of spin-orbit coupling and crystal symmetry.

Findings

Significant in-plane and out-of-plane anisotropies in tunnel transmission

Anisotropies arise from spin-orbit coupling and cubic anisotropy

Low C2v symmetry influences the electronic properties

Abstract

Using an advanced tight-binding approach, we estimate the anisotropy of the tunnel transmission associated with the rotation of the 5/2 spin of a single Mn atom forming an acceptor state in GaAs and located near an AlGaAs tunnel barrier. Significant anisotropies in both in-plane and out-of-plane geometries are found, resulting from the combination of the large spin-orbit coupling associated with the p-d exchange interaction, cubic anisotropy of heavy-hole dispersion and the low C2v symmetry of the chemical bonds.