The core structure and Peierls potential of dislocations in Al

Abstract

With the Peierls model reformulated as variational procedure the core structure of screw and edge dislocations in Al is studied for a set of different γ-surfaces from the literature. When the same input parameters are used, the agreement with the simulations of the atomic arrangement in the core region obtained by using EAM potentials or by DFT methods is excellent. In addition it is also possible to derive the Peierls energy and the Peierls stress with nearly negligible computational effort on a laptop. It turns out that small variations in the topology of the γ-surface can lead to drastic changes in the Peierls energy up to a factor of nearly three. Unless the existing uncertainties in the DFT calculations of γ-surfaces are removed, it is not possible to derive reliable value for the Peierls energy or the kink energy in Al and also other fcc metals.