The role of defects in the tensile properties of silicene

Abstract

Effects of vacancies and Stone–Wales defects on the mechanical properties of silicene are investigated through molecular dynamic finite element method with Tersoff potential. Young’s modulus, Poisson’s ratio and uniaxial tensile stress–strain curves are considered in the armchair and zigzag directions. It is found that pristine and lowly defective silicene sheets exhibit almost the same elastic nature up to fracture points. However, a single defect weakens significantly the silicene sheet, resulting in a considerable reduction in the fracture strength. One 2-atom vacancy in the sheet’s center reduces 18–20 % in fracture stress and 33–35 % in fracture strain. The weakening effects of Stone–Wales defects vary with the tensile direction and the orientation of these defects.