First-principles plane-wave pseudopotential calculations were used to study the electronic structures, structural optimization, and formation energies of intrinsic vacancies in bulk SrTiO3. The anion and cation vacancy-induced levels appeared near to the valence- and conduction-band edges in the band gap. The formation energies of isolated vacancies with different charge states were obtained, and the defect reaction energies, such as Sr partial Schottky (VSr2–+VO2+), Ti partial Schottky (VTi4–+2VO2+), and full Schottky (VSr2–+VTi4–+3VO2+) were also evaluated. It was found that depending on the atomic chemical potentials, the relative stability of the defect species or reactions was different. The overall trend of the stable defect structures could explain the electrical conductivity of SrTiO3 for different chemical environments experimentally observed.

First-Principles Study on Structures and Energetics of Intrinsic Vacancies in SrTiO3. T.Tanaka, K.Matsunaga, Y.Ikuhara, T.Yamamoto: Physical Review B, 2003, 68[20], 205213 (8pp)