Electron-induced stabilization of ferromagnetism in GaGdN

TL;DR

This paper demonstrates that electron doping can stabilize ferromagnetism in GaGdN alloys, explaining colossal magnetic moments through a model involving donor electron polarization, differing from traditional transition metal-doped GaN.

Contribution

It introduces a novel mechanism for stabilizing ferromagnetism in GaGdN via electron doping and provides a theoretical explanation for large magnetic moments observed experimentally.

Findings

Electron doping stabilizes ferromagnetism in GaGdN.

Gd-Gd coupling is antiferromagnetic without doping.

A model explains colossal magnetic moments through donor electron polarization.

Abstract

Using {\it ab initio} band structure calculations and symmetry arguments, we show that the magnetic property of Ga$_{1-x}$Gd$_x$N is drastically different from TM-doped GaN. The coupling between Gd atoms in the alloy is antiferromagnetic, but the ferromagnetic phase can be stabilized by introducing electrons. Furthermore, we propose a model that may explain the recently observed colossal magnetic moments in this system, based on the polarization of donor electrons.