Simulations of crack initiation in silicon

The applicability of semiempirical potential energy models for describing crack initiation in covalently bonded silicon has been studied using classical molecular dynamics (MD) approach. For describing interatomic interactions, in this approach we use the recently developed environment dependent interatomic potential (EDIP) with two- and three-body terms. Since the original form of this potential was found problematic in describing bond-breaking properties we tested three different modifications of it. An additional point of interest in this study were crack tip structures observed preceding the actual fracture. Our results, with an idealized simulation setup, indicated formation of stable ring-like structures. Unless angular forces were made relatively strong, these ring-like structures were formed near the crack tip before and even during the crack initiation. These relatively stable structures could cause crack initiation to stop temporarily, especially at early stages of fracture.