Valence electron energy loss study of Fe-doped SrTiO3 and a Σ13 boundary: electronic structure and dispersion forces

Valence electron energy loss spectroscopy in a dedicated scanning transmission electron microscope has been used to obtain the interband transition strength of a Σ13 tilt grain boundary in SrTiO3. In a first step the electronic structure of bulk SrTiO3 has been analysed quantitatively by comparing VEELS spectra with vacuum ultraviolet spectra and with ab initio density of states calculations. The electronic structure of a near Σ13 grain boundary and the corresponding dispersion forces were then determined by spatially resolved VEELS. Also the effects of delocalization of the inelastic scattering processes were estimated and compared with results from the literature.