Optimally Designed Digitally-Doped Mn:GaAs

TL;DR

This study employs ab initio calculations to analyze exchange interactions in digitally doped Mn:GaAs, aiming to optimize the Curie temperature through crystallographic and doping strategies, potentially achieving room-temperature ferromagnetism.

Contribution

It introduces a method to optimize Tc in Mn:GaAs by analyzing and exploiting crystallographic dependence of exchange interactions via digital doping and hole doping strategies.

Findings

Antiferromagnetic interactions can be minimized through specific delta-doping orientations.

Hole doping with Be significantly increases predicted Tc.

Optimized doping strategies could enable room-temperature ferromagnetism in Mn:GaAs.

Abstract

We use the ab initio local-density approximation (LDA) to study of exchange interactions and Tc of Ga1−xMnxAs grown in digitally doped structures. We analyze the crystallographic dependence of exchange interactions predicted by the LDA in terms of the Mn t2 and e levels, and explain the origin of the antiferromagnetic contribution to the total exchange interactions. We exploit this dependence and consider delta-doping in specific orientations where the antiferromagnetic interactions are minimized, to optimize Tc of the system. By including hole doping with the addition of Be in the GaAs host digitally doped Ga1−xMnxAs is predicted to be significantly above room temperature.