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 dislocations, as in Si, the classic theory leads to gross overestimation of the barrier to dislocation motion. We present a new, semidiscrete theory which corrects the inconsistencies of the classic theory, and gives results remarkably similar to actual atomistic calculations, both qualitatively and quantitatively. Our theory provides a link between accurate nanometer-scale quantum mechanical calculations of the dislocation core energetics to mesoscale continuum descriptions.