Article ID Journal Published Year Pages File Type
8155402 Journal of Magnetism and Magnetic Materials 2017 10 Pages PDF
Abstract
Magnetic properties of Ga vacancies VGa and vacancy pairs in GaN are analyzed by employing the Generalized Gradient Approximation with the +U corrections. Strong spin polarization stabilizes high spin configurations of VGa, and leads to its negative-Ueff character. Both features are reflected in the magnetic properties of vacancies pairs. Because of electron transfer between two vacancies induced by negative-Ueff, both vacancies can be in different charge and spin states, and thus the spin ground states of a pair can be ferrimagnetic rather than ferro- or antiferromagnetic. Magnetic coupling of VGa-VGa pairs as a function of separation between the defects, their relative orientation, and of the charge state, was calculated. The strength of magnetic coupling is reduced by the U-induced localization of the wave functions. The obtained results show that gallium vacancies can lead to the observed ferromagnetism in irradiated GaN samples.
Related Topics
Physical Sciences and Engineering Physics and Astronomy Condensed Matter Physics
Authors
, ,