High-energy spectroscopic study of the III-V nitride-based diluted magnetic semiconductor Ga$_{1-x}$Mn$_{x}$N

TL;DR

This study investigates the electronic structure of Ga$_{1-x}$Mn$_{x}$N, revealing Mn ions are divalent in a tetrahedral crystal field, with new in-gap states forming upon doping, and a stronger p-d exchange coupling than in Ga$_{1-x}$Mn$_{x}$As.

Contribution

The paper provides detailed spectroscopic analysis of Mn-doped GaN, showing the valence state, in-gap states, and stronger exchange coupling, which advances understanding of its magnetic properties.

Findings

Mn ions are divalent in tetrahedral crystal field.

New states form within the band gap upon Mn doping.

The p-d exchange coupling is stronger than in GaMnAs.

Abstract

We have studied the electronic structure of the diluted magnetic semiconductor Ga$_{1-x}$Mn$_{x}$N ($x$ = 0.0, 0.02 and 0.042) grown on Sn-doped $n$-type GaN using photoemission and soft x-ray absorption spectroscopy. Mn $L$-edge x-ray absorption have indicated that the Mn ions are in the tetrahedral crystal field and that their valence is divalent. Upon Mn doping into GaN, new state were found to form within the band gap of GaN, and the Fermi level was shifted downward. Satellite structures in the Mn 2$p$ core level and the Mn 3$d$ partial density of states were analyzed using configuration-interaction calculation on a MnN$_{4}$ cluster model. The deduced electronic structure parameters reveal that the $p$-$d$ exchange coupling in Ga$_{1-x}$Mn$_{x}$N is stronger than that in Ga$_{1-x}$Mn$_{x}$As.