First Principles Electronic Structure of Mn doped GaAs, GaP, and GaN semiconductors

TL;DR

This paper uses advanced first-principles calculations to accurately determine the electronic and magnetic properties of Mn-doped GaAs, GaP, and GaN semiconductors, validating models and proposing methods to estimate localized level energies.

Contribution

It demonstrates the importance of self-interaction correction methods for accurate electronic ground state predictions in magnetic semiconductors.

Findings

SIC-LSD predicts correct ground state configurations.

Excellent agreement with experimental magnetic moments.

Proposes methods to estimate binding energies of localized levels.

Abstract

We present first-principles electronic structure calculations of Mn doped III-V semiconductors based on the local spin-density approximation (LSDA) as well as the self-interaction corrected local spin density method (SIC-LSD). We find that it is crucial to use a self-interaction free approach to properly describe the electronic ground state. The SIC-LSD calculations predict the proper electronic ground state configuration for Mn in GaAs, GaP, and GaN. Excellent quantitative agreement with experiment is found for magnetic moment and p-d exchange in (GaMn)As. These results allow us to validate commonly used models for magnetic semiconductors. Furthermore, we discuss the delicate problem of extracting binding energies of localized levels from density functional theory calculations. We propose three approaches to take into account final state effects to estimate the binding energies of the Mn-d levels in GaAs. We find good agreement between computed values and estimates from photoemisison experiments.