Ab InitioTheory of Dislocation Interactions: From Close-Range Spontaneous Annihilation to the Long-Range Continuum Limit

Parallel supercomputer technology now permits ab initio studies of systems of sufficient size to explore the interactions among dislocations in a solid. This study shows that the silicon shuffle-set (110) screw dislocation is stable against spontaneous dissociation, provides an ab initio value for the dislocation core energy, demonstrates a dislocation-antidislocation interaction approaching the classical limit within a few tens of angstroms, and reveals a pathway for the spontaneous mutual annihilation of a dislocation dipole of the type that occurs when a Frank-Read source emits a dislocation loop.