The unexpected magnetism in 2D group-IV-doped GaN for spintronic applications

TL;DR

This study uses first-principles calculations to explore how group-IV doping affects the magnetic properties of monolayer GaN, revealing potential for spintronic applications with specific dopants and conditions.

Contribution

It provides a systematic theoretical analysis of the structural and magnetic properties of group-IV-doped monolayer GaN, identifying conditions for stable magnetism.

Findings

Ge and Sn dopants induce magnetic moments of 1 μB per atom.

N-rich growth conditions favor dopant substitution and magnetism.

Intrinsic vacancies suppress magnetic moments of dopants.

Abstract

In this study, the structural and magnetic properties of group-IV-doped monolayer GaN were systematically investigated by first-principles calculations. Among all the group-IV dopants, only Ge and Sn atoms prefer to substitute the Ga atom of monolayer GaN and form a buckling structure with a magnetic moment of 1 $\mu_B$ per dopant. The N-rich growth conditions are more desirable for such a substitution process than the Ga-rich grow conditions. With a large diffusion barrier vertical to the monolayer GaN, both Ge and Sn atoms tend to stay on the same side of monolayer GaN with an antiferromagnetic coupling between them. When intrinsic vacancies exist in monolayer GaN, the magnetic moments of group-IV dopants vanish due to the charge transferring from the dopants to Ga or N vacancies. The precondition creation of Ga vacancies, a plentiful supply of Ge or Sn dopants, and the N-rich conditions can be adopted to maintain the magnetic properties of group-IV-doped monolayer GaN. These theoretical results help to promote the applications of 2D GaN-based materials in spintronics.