Peierls potential and kink-pair mechanism in high-pressureMgSiO3perovskite: An atomic scale study

The motion of [100](010) screw dislocations via a kink-pair mechanism is investigated in high-pressure ${\mathrm{MgSiO}}₃$ perovskite by means of atomistic calculations and an elastic interaction model for kink nucleation. Atomistic calculations based on the nudged elastic band method provide the Peierls potential, which is shown to be dynamically asymmetric and stress dependent. The elastic interaction model adjusted to match kink width computed atomistically, is used to evaluate the critical nucleation enthalpy. We demonstrate that the kink-pair mechanism in ${\mathrm{MgSiO}}₃$ perovskite is controlled by the nucleation of kinks along the [100] screw dislocation.