The energy levels of defects were calculated by using the tight-binding Greens function method and were compared with experimental data. The method was very useful for displaying chemical trends in defect energy levels. It was found that the Ti and O vacancies were shallow. Transition-metal impurities at the octahedral ion site were found to give rise to numerous charge states because of the large intra-atomic electron repulsion. The levels were generally in the high-spin configuration, except for the high-valence transition metals. The levels of Cr4+, Fe4+ and Co4+ lay near to the mid-gap. The Ti3+ trapped electron centers became deep at higher Zr contents in Pb(Zr,Ti)O3.

Energy Levels of Point Defects in SrTiO3 and Related Oxides. J.Robertson: Journal of Applied Physics, 2003, 93[2], 1054-9