Valence band photoelectron emission of SrTiO3 analyzed with X-ray standing waves

The X-ray standing wave technique is used for a site specific analysis of the valence band of SrTiO3. The determined partial photoelectron yields reveal the hybridization of metal and oxygen derived states. Fitting ab initio   calculated density of states to the data yields solid state photoelectric cross sections, which are much larger than for corresponding atomic states for Ti 4s and Sr 5s. Valence band features are significantly broader than predicted by single particle band structure calculations in particular for oxygen derived states. This can, at least in part, be explained by correlation effects.