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.

中文翻译：

---

SrNbO3 和 SrTiO3 中的电子空位散射：非平衡格林函数的密度泛函理论研究

氧空位通常归因于钙钛矿氧化物材料电子传输的变化（${\mathrm{ABO血型}}_3$）。在这里，我们使用密度泛函理论与非平衡格林函数相结合来系统地研究 O 空位的影响，并且还$A$- 和$乙$-电子传输上的位点空缺，其特征在于散射截面。我们认为${\mathrm{铌酸锶}}_3$和$n$-类型${\mathrm{钛酸锶}}_3$以及块体和薄膜（板）几何形状的对比结果。通过改变电子掺杂${\mathrm{钛酸锶}}_3$我们深入了解电子空位散射在不同实验条件下如何变化。我们观察到散射截面显着增加（以方格参数为单位）$A^2$） 从$\approx 0.5\text{–}2.5A^2$每个空缺职位${\mathrm{铌酸锶}}_3$和重掺杂${\mathrm{钛酸锶}}_3$到超过$9A^2$在${\mathrm{钛酸锶}}_3$每个晶胞有 0.02 个自由载流子。此外，O空位的散射强度增强${\mathrm{二氧化钛}}_2$低掺杂的终止表面超过 6 倍${\mathrm{钛酸锶}}_3$与板坯和散装系统中的其他位置相比。有趣的是，我们还发现 Sr 空位从可以忽略不计的散射中心${\mathrm{铌酸锶}}_3$和重掺杂${\mathrm{钛酸锶}}_3$，在弱掺杂中具有大的散射截面${\mathrm{钛酸锶}}_3$。因此，我们得出结论，这些系统中的电子空位散射对电子浓度和空位位置的组合敏感。