ATOMISTIC STUDY OF THE STRENGTH AND ELASTIC CONSTANTS OF PERFECT AND DEFECTED SILICON

Abstract

The effects of vacancies on the strength and elastic constants of silicon, such as Young's modulus and Poisson's ratio are investigated using the molecular dynamics simulations with the Stillinger–Weber potential. The defected crystalline cells contain randomly generated defect distributions in the simulation models. The ideal strength is found to be 33.6 GPa at the strain 0.26. The Young's modulus and Poisson's ratio is 148 GPa and 0.252, respectively. It is found that the strength decreases as the point defect fraction increases, and the variation of the strength versus the point defect fraction coincides with a decaying exponential function. In addition, vacancies are shown to reduce the elastic constants. In general, the elastic constants of silicon vary linearly versus the defect fraction.