Interatomic potential for condensed phases and bulk defects in silicon

We present a new empirical potential for silicon which is a considerable improvement over existing models in describing structures away from equilibrium, such as bulk defects. The interatomic interaction is described by two-and three-body terms using theoretically motivated functional forms which emphasize chemical and physical trends. The numerical parameters in the functional forms are obtained by fitting to several ab initio calculations, which include bulk phases and defect structures. The model is tested to core properties of partial dislocations in the glide set {111}, which are not included in the database, and gives results in very good agreement with ab initio calculations. This is the only known potential capable of describing the structure of both the 30 degrees- and 90 degrees-partial dislocations.