Anti-ferrodistortive-Like Oxygen-Octahedron Rotation Induced by the Oxygen Vacancy in Cubic SrTiO3

New insights into the atomistic and electronic structure of the oxygen vacancy in SrTiO3 are presented through first-principles calculations. The oxygen vacancy induces a local anti-ferrodistortive-like oxygen-octahedron rotation, even in the cubic phase. This feature leads to localized electronic states in the bandgap, giving an excellent explanation to the thermal ionization and optical transition observed experimentally.