First-principles study of the magnetization of oxygen-depleted In(2)O(3)(001) surfaces

The origin of the magnetism in some oxide-based diluted magnetic semiconductors is still a puzzle. In this work, significantly ferromagnetic states of the oxygen-depleted In(2)O(3)(001) surfaces are investigated on the basis of first-principles density functional calculations. Our results show that the perfect oxygen-depleted surfaces are nonmagnetic; however, the surface states become ferromagnetic with the appearance of vacancies on the most outward In sites. The origin of the surface state magnetization can be explained using the Stoner model, and the exchange coupling between surfaces In s-p hybridization orbitals implies a ferromagnetic ground state. Our investigation gives a reasonable explanation for the source of the magnetism in oxygen-depleted In(2)O(3) nanostructures observed in previous experiments.