Simulations of crack initiation in silicon

The applicability of semiempirical potential energy models for describing c rack initiation in covalently bonded silicon has been studied using classic al molecular dynamics (MD) approach. For describing interatomic interaction s, in this approach we use the recently developed environment dependent int eratomic potential (EDIP) with two- and three-body terms. Since the origina l form of this potential was found problematic in describing bond-breaking properties we tested three different modifications of it. An additional poi nt of interest in this study were crack tip structures observed preceding t he actual fracture. Our results, with an idealized simulation setup, indica ted formation of stable ring-like structures. Unless angular forces were ma de relatively strong, these ring-like structures were formed near the crack tip before and even during the crack initiation, These relatively stable s tructures could cause crack initiation to stop temporarily, especially at e arly stages of fracture. (C) 2000 Elsevier Science B.V. All rights reserved .