Oxygen vacancies are often attributed to changes in the electronic transport for perovskite oxide materials (${\mathrm{ABO}}_3$). 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 ${\mathrm{SrNbO}}_3$ and $n$-type ${\mathrm{SrTiO}}_3$ and contrast results for bulk and thin film (slab) geometries. By varying the electron doping in ${\mathrm{SrTiO}}_3$ 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 $a^2$) from $\approx 0.5\text{–}2.5a^2$ per vacancy in ${\mathrm{SrNbO}}_3$ and heavily doped ${\mathrm{SrTiO}}_3$ to more than $9a^2$ in ${\mathrm{SrTiO}}_3$ with 0.02 free carriers per unit cell. Furthermore, the scattering strength of O vacancies is enhanced in ${\mathrm{TiO}}_2$ terminated surfaces by a factor of more than 6 in lowly doped ${\mathrm{SrTiO}}_3$ compared to other locations in slabs and bulk systems. Interestingly, we also find that Sr vacancies go from being negligible scattering centers in ${\mathrm{SrNbO}}_3$ and heavily doped ${\mathrm{SrTiO}}_3$, to having a large scattering cross section in weakly doped ${\mathrm{SrTiO}}_3$. We therefore conclude that the electron-vacancy scattering in these systems is sensitive to the combination of electron concentration and vacancy location.

• Received 12 January 2024
• Revised 5 April 2024
• Accepted 26 April 2024

DOI:https://doi.org/10.1103/PhysRevB.109.205129