Modeling dislocation cores inSrTiO3using the Peierls-Nabarro model

Abstract

We have recently determined dislocation core structures in complex minerals relevant to the Earth's mantle using the Peierls-Nabarro model. In this approach, the original Peierls-Nabarro model is coupled with first-principles calculations of generalized stacking fault. In order to test the reliability of such calculations, we study here the dislocation core properties in a perovskite-structured material, $\mathrm{Sr}\mathrm{Ti}{\mathrm{O}}_{3}$, for which a lot of experimental information are available. Four different slip systems have been investigated in $\mathrm{Sr}\mathrm{Ti}{\mathrm{O}}_{3}$: ⟨100⟩{010}, ⟨100⟩{011}, ⟨110⟩{001}, and $⟨110⟩{1\overline{1}0}$. $⟨110⟩{1\overline{1}0}$ exhibits the lower lattice friction due to core spreading, and the next easiest slip system is found to be ⟨100⟩{010}. It is shown that our results (dislocation core spreading and Peierls stress values) are in perfect agreement with experiments (transmission electron microscopy model of core structure and mechanical properties), providing an interesting validation of the Peierls-Nabarro model on complex materials.