Structural transformation, amorphization, and fracture in nanowires: A multimillion-atom molecular dynamics study

Multimillion-atom molecular dynamics simulations of silicon diselenide nano wires are used to study mechanical properties and changes in nanowire struc ture under strain. The nanowires transform from a body-centered orthorhombi c structure to a body-centered tetragonal structure under uniaxial strain, which causes an unexpected elongation in one of the transverse directions. For larger strains, the nanowires undergo a process of local amorphization, followed by fracture at one of the resulting crystalline-amorphous interfa ces. The critical strain for fracture is 15%. Local temperature and stress distributions after failure are interpreted in terms of the local amorphiza tion. (C) 2001 American Institute of Physics.