Doping Dependent Changes in Nitrogen 2$p$ States in the Diluted Magnetic Semiconductor Ga$_{1-x}$Cr$_{x}$N

TL;DR

This study investigates how doping with chromium affects the nitrogen 2$p$ electronic states in the dilute magnetic semiconductor Ga$_{1-x}$Cr$_{x}$N, revealing changes linked to ferromagnetism through spectroscopic analysis.

Contribution

It provides a systematic spectroscopic analysis of nitrogen states in Ga$_{1-x}$Cr$_{x}$N and links electronic structure changes to ferromagnetic properties, confirming Cr substitutional doping.

Findings

Cr doping alters N 2$p$ states in GaN

Changes in N 2$p$ DOS correlate with ferromagnetism

Spectroscopy confirms Cr substitution at Ga sites

Abstract

We study the electronic structure of the recently discovered diluted magnetic semiconductor Ga$_{1-x}$Cr$_{x}$N ($x$ = 0.01-0.10). A systematic study of the changes in the $occupied$ and $unoccupied$ ligand (N) partial density of states (DOS) of the host lattice is carried out using N 1$s$ soft x-ray emission and absorption spectroscopy, respectively. X-ray absorption measurements confirm the wurtzite N 2$p$ DOS and substitutional doping of Cr into Ga-sites. Coupled changes in the $occupied$ and $unoccupied$ N 2$p$ character DOS of Ga$_{1-x}$Cr$_{x}$N identify states responsible for ferromagnetism consistent with band structure calculations.