First-principles calculations were used to study the role of vacancy defects (VO, and VTi) in the magnetism of ultra-thin titanium oxide nanosheet (UTiO2NS). It was shown that VTi defects could trigger spin-polarization and collective ferromagnetism at room temperature, making UTiO2NS half-metallic, whereas the UTiO2NS containing VO defects was an antiferromagnetic semiconductor with a small gap. The coexistence of VO and VTi defects narrowed the band gap of UTiO2NS by ~40%. The half-metallicity and the band gap narrowing indicated the potential applications of UTiO2NS in spintronics and solar-energy harvesting.

Vacancy-Defect–Derived Magnetism in Titanium Oxide Nanosheet: a First-Principles Study. T.He, M.Zhao, L.Mei: EPL, 2010, 90[6], 66005