First-principles calculations on the magnetism of Ti-defected lepidocrocite-related TiO2 nanosheet

Abstract

Using first-principles calculations, this paper reports a systematic research on the magnetic properties of the Ti-defected lepidocrocite-related TiO2 nanosheets. Results show that the system magnetic moment depends on the number of Ti vacancies in the supercell. Further detailed research on the Ti-defected Ti17O36 system indicates that the magnetism mainly originates from the six nearest-neighboring O atoms of the Ti vacancy, specifically, more from the two one-fold coordinated and less from the four three-fold coordinated. The corresponding electronic band structures show that this Ti-defected Ti17O36 system becomes half-metal. Discussion on the magnetic ground states indicates that, for the Ti68O144 system with four Ti vacancies in equivalent positions, the ferromagnetic state is the magnetic ground state, and the estimated Curie temperature is about 28 K. In general, this Ti-defected lepidocrocite-related TiO2 nanosheet represents a novel kind of material. Research on the magnetic properties reported in this paper can enrich the theoretical knowledge.