Spin-Orbit Effects in Diluted Magnetic Semiconductors

TL;DR

This theoretical study explores how spin-orbit coupling and exchange interactions influence magnetic and electronic properties in diluted magnetic semiconductors, revealing effects like impurity band splitting and potential insulating phases.

Contribution

It introduces a realistic band structure approach that extends beyond mean-field models to analyze spin-orbit effects in diluted magnetic semiconductors.

Findings

Strong exchange potentials bind carriers near impurities.

Spin-orbit coupling affects spin polarization, especially at weak coupling.

Impurity band splitting can lead to a new insulating phase at low doping.

Abstract

We present a theoretical study of diluted magnetic semiconductors that treats the local sp-d exchange interaction J between the itinerant carriers and the Mn d electrons within a realistic band structure and goes beyond previous mean-field approaches. In case of (Ga,Mn)As, we find that strong exchange potentials tightly bind carriers near impurity sites. Spin-orbit coupling is found to have a more pronounced effect on spin polarization at weak coupling and this feature can be exploited for magnetotransport. For low doping regime, we predict that spin-orbit coupling splits impurity bands and can induce a novel insulating phase.