Atomistic simulations and Peierls–Nabarro analysis of the Shockley partial dislocations in palladium

Abstract

A detailed study of Shockley partials in Pd is presented, using a full-scale atomistic simulation of the structure and energetics of the dislocation motion. The interatomic potential is derived by fitting to data from first-principles electron-structure calculations. The outcome from the atomistic simulation is compared with the corresponding results using the Peierls–Nabarro (PN) model. The required input to the PN model is determined from the interatomic potential used in the atomistic simulation in order to make the comparison as decisive as possible. We find that the core, obtained in the atomistic simulation, is much wider and extends over a larger region compared with the PN model. A modification of the PN model is suggested to make it more consistent with the atomistic description. Using the modified version of the PN model improves the core structure considerably. The magnitude of the Peierls barrier from the atomistic simulation is in reasonable agreement with both experimental data and the corresponding values obtained using the PN model.