Elastic properties and large deformation of two-dimensional silicene nanosheets using molecular dynamics

This paper aims to compute the elastic properties and large deformation of two-dimensional silicene, a low buckled honeycomb structure of silicon, under uniaxial and biaxial tension by implementing molecular dynamics simulations in canonical ensemble (NVT). The results demonstrate that Young's and bulk moduli and ultimate stress of silicene nanosheet are lower than those of graphene. Ultimate strain is found to be higher than that of graphene for armchair silicene, unlike the zigzag one. Moreover, Poisson's ratio of silicene is found to be greater than that of its carbon counterpart due to longer Si-Si bond length and its low buckled honeycomb structure. Further, it is observed that bulk modulus is strongly size-dependent and it decreases by increasing the length of nanosheet. Finally, the silicene behavior under large deformation and fracture pattern are investigated and the formation of topological defects and silicon chains are observed. It is further revealed that the silicene is noticeably weaker than graphene in zigzag direction.