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Oxygen vacancies are often attributed to changes in the electronic transport for perovskite oxide materials (ABO3). Here, we use density functional theory coupled with nonequilibrium Green's functions to systematically investigate the influence of O vacancies and also A- and B-site vacancies, on the electronic transport as characterized by a scattering cross section. We consider SrNbO3 and n-type SrTiO3 and contrast results for bulk and thin film (slab) geometries. By varying the electron doping in SrTiO3 we get insight into how the electron-vacancy scattering varies for different experimental conditions. We observe a significant increase in the scattering cross section (in units of square-lattice parameter a2) from ≈0.5-2.5a2 per vacancy in SrNbO3 and heavily doped SrTiO3 to more than 9a2 in SrTiO3 with 0.02 free carriers per unit cell. Furthermore, the scattering strength of O vacancies is enhanced in TiO2 terminated surfaces by a factor of more than 6 in lowly doped SrTiO3 compared to other locations in slabs and bulk systems. Interestingly, we also find that Sr vacancies go from being negligible scattering centers in SrNbO3 and heavily doped SrTiO3, to having a large scattering cross section in weakly doped SrTiO3. We therefore conclude that the electron-vacancy scattering in these systems is sensitive to the combination of electron concentration and vacancy location.
Rosendal et al. (Mon,) studied this question.