SEMIDISCRETE VARIATIONAL PEIERLS FRAMEWORK FOR DISLOCATION CORE PROPERTIES

The classic Peierls theory of dislocations is critically examined and shown to contain a number of inconsistencies. For narrow core dislocat ions, as in Si, the classic theory leads to gross overestimation of th e barrier to dislocation motion. We present a new, semidiscrete theory which corrects the inconsistencies of the classic theory, and gives r esults remarkably similar to actual atomistic calculations, both quali tatively and quantitatively. Our theory provides a link between accura te nanometer-scale quantum mechanical calculations of the dislocation core energetics to mesoscale continuum descriptions.