Tuning magnetism of monolayer GaN by vacancy and nonmagnetic chemical doping

• GaN monolayer has graphene-like structure and is nonmagnetic.
• A neutral Ga vacancy induces 3 μB magnetic moment in g-GaN.
• Magnetism of g-GaN with Ga vacancy can be tuned by various Mg/Si doping concentrations.

In view of important role of inducing and manipulating the magnetism in 2D materials for the development of low-dimensional spintronic devices, the magnetism of GaN monolayer with Ga vacancy and nonmagnetic chemical doping are investigated using first-principles calculations. It is found that pure GaN monolayer has graphene-like structure and is nonmagnetic. While, a neutral Ga vacancy can induce 3 μB intrinsic magnetic moment, localized mainly on the neighboring N atoms. Interestingly, after one Mg or Si atom doping in g-GaN with Ga vacancy, the magnetic moment can be modified to 4 μB or 2 μB respectively due to the change in hole number. Meantime, Mg-doped g-GaN with Ga vacancy shows half-metal character. With the increasing of doping concentrations, the magnetic moment can be further tuned. The results are interesting from a theoretical point of view and may open opportunities for these 2D GaN based materials in magnetic devices.