Compositional Dependence of Formation Energies of Substitutional and Interstitial Mn in Partially Compensated (Ga,Mn)As

TL;DR

This study uses density-functional theory to analyze how the formation energies of substitutional and interstitial Mn in (Ga,Mn)As depend on dopant concentrations, revealing a self-compensation mechanism affecting material properties.

Contribution

It provides a detailed theoretical analysis of the compositional dependence of Mn formation energies, highlighting the self-compensation behavior in (Ga,Mn)As.

Findings

Formation energy depends on Mn positions and dopant levels

Partial Mn concentrations increase proportionally with total Mn

Self-compensation mechanism influences material properties

Abstract

We use the density-functional theory to calculate the total energy of mixed crystals (Ga,Mn)As with a small concentration of various donors. We find that the formation energy of Mn depends strongly on the partial concentrations of Mn in the substitutional and interstitial positions, and on the concentration of other dopants. The composition dependence of the formation energies represents an effective feedback mechanism, resulting in the self-compensation property of (Ga,Mn)As. We show that the partial concentrations of both substitutional and interstitial Mn increase proportionally to the total concentration of Mn.