Modelling 100 and 010 screw dislocations in MgSiO3 perovskite based on the Peierls-Nabarro-Galerkin model

K Gouriet and P Carrez and P Cordier, MODELLING AND SIMULATION IN MATERIALS SCIENCE AND ENGINEERING, 22, 025020 (2014).

DOI: 10.1088/0965-0393/22/2/025020

In this study, we model the core structure of screw dislocations with 1 0 0 and 0 1 0 Burgers vector in MgSiO3 perovskite, in the pressure range of Earth's lower mantle (25-130 GPa). We use a generalized Peierls-Nabarro model, called Peierls-Nabarro-Galerkin, based on generalized stacking-fault energy calculations. These stacking-fault energy calculations are performed using a pairwise potential parametrization and compared to ab initio results. The results of Peierls-Nabarro-Galerkin calculations demonstrate that 1 0 0 dislocation and 0 1 0 are, respectively, characterized by a planar core spreading in (0 1 0) and (1 0 0). Our results emphasize the role of 1 0 0(0 1 0) and 0 1 0(1 0 0) slip systems in the deformation mechanism of MgSiO3 perovskite. Furthermore, we validate the use of pairwise potential for further dislocation modelling of such minerals at the atomic scale.

Return to Publications page