Defect-induced ferromagnetism in rutile TiO2: A first-principles study

Based on first-principles calculations, the electronic and magnetic properties of undoped and Li-doped rutile TiO2 have been studied. The results demonstrate that a cation vacancy can arouse ferromagnetism in TiO2 and the magnetic moment mainly comes from p orbitals of O atoms around the Ti vacancy. However, the Ti vacancy under normal conditions is very difficult to form due to its high formation energy. Our calculations indicate that Li-doped TiO2 can reduce the formation energy while keeping the magnetism. The large magnetization energy indicates that Li-doped TiO2 is a promising room-temperature diluted magnetic semiconductor.