Vacancy-defect–derived magnetism in titanium oxide nanosheet: A first-principles study

School of Physics and State Key Laboratory of Crystal Materials, Shandong University - Jinan 250100, China

^* zmw@sdu.edu.cn

Received: 28 April 2010
Accepted: 1 June 2010

Abstract

We perform first-principle calculation to study the role of vacancy defects (V_O, and V_Ti) in the magnetism of ultra-thin titanium oxide nanosheet (UTiO₂NS). We show that V_Ti defects can trigger spin-polarization and collective ferromagnetism at room temperature, making UTiO₂NS half-metallic, whereas the UTiO₂NS containing V_O defects is an antiferromagnetic semiconductor with a small gap. The coexistence of V_O and V_Ti defects narrows the band gap of UTiO₂NS by ∼40 %. The half-metallicity and the band gap narrowing indicate the potential applications of UTiO₂NS in spintronics and solar-energy harvesting.