Peierls potential and kink-pair mechanism in high-pressure MgSiO3 perovskite: An atomic scale study

摘要

The motion of [100]( 010) screw dislocations via a kink-pair mechanism is investigated in high-pressure MgSiO3 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 MgSiO3 perovskite is controlled by the nucleation of kinks along the [100] screw dislocation.