Anisotropic motion of point defects near edge dislocations

We calculated the formation energy and the migration energy of vacancies near perfect edge dislocations in Cu. Effective vacancy volume in the most compressive site (the dislocation core) was 94.3% of that in the perfect lattice. The vacancy formation energy only in the most compressive site was conspicuously low (0.74 eV), and the energy in other sites was almost equal to that in the perfect lattice. As the vacancy got close to the dislocation core from the compression side, the vacancy migration energy in the direction of the Burgers vector and also on the extra half plane decreased. Calculated migration energies suggest the trapping of vacancies on the compression side of the edge dislocation and the de-trapping at high temperatures. (C) 2004 Published by Elsevier B.V.