Defect-induced magnetism in nitride and oxide nanowires: Surface effects and quantum confinement

Defect-induced local moment formation in GaN and ZnO nanowires is investigated using density functional theory-based first-principles electronic-structure methods. We find that quantum confinement and surface effects, coupled with strong structural relaxations in nanowires, significantly enhance the spin-polarization energy and reduce the defect formation energy. These results are consistent with the fact that unconventional magnetism is often found in nanostructures and thin films.