Nitrogen defects and ferromagnetism of Cr-doped AlN diluted magnetic semiconductor from first principles

TL;DR

This paper uses first-principles calculations to study nitrogen defects in Cr-doped AlN semiconductors, revealing their role in high-temperature ferromagnetism relevant for spintronics.

Contribution

It provides a detailed first-principles analysis of nitrogen vacancies and their impact on ferromagnetism in Cr-doped AlN, aligning with experimental findings.

Findings

Nitrogen vacancies enhance ferromagnetism in Cr-doped AlN.

Results agree with experimental observations of high Curie temperatures.

Insights into defect-induced ferromagnetism mechanisms in diluted magnetic semiconductors.

Abstract

High Curie temperature of 900 K has been reported in Cr-doped AlN diluted magnetic semiconductors prepared by various methods, which is exciting for spintronic applications. It is believed that N defects play important roles in achieving the high temperature ferromagnetism in good samples. Motivated by these experimental advances, we use a full-potential density-functional-theory method and supercell approach to investigate N defects and their effects on ferromagnetism of (Al,Cr)N with N vacancies (V_N). Calculated results are in agreement with experimental observations and facts of real Cr-doped AlN samples and their synthesis. Our first-principles results are useful to elucidating the mechanism for the ferromagnetism and exploring high-performance Cr-doped AlN diluted magnetic semiconductors.