Defect-sensitive performance of silicene sheets under uniaxial tension: mechanical properties, electronic structures and failure behavior

Abstract

As a silicon analog of graphene, silicene has attracted considerable attention due to its unique physical and chemical properties. Pioneering studies have demonstrated that defects in graphene-like two-dimensional materials are considered tools for tuning the physical properties of these materials. In this work, the influence of defects on the mechanical properties and failure behavior of silicene sheets were investigated using molecular mechanics and molecular dynamics methods. The results showed that the intrinsic strength of the silicene sheets decreased with increased linear density for vacancies, width ratio for cracks, and inflection angle for grain boundaries. The elastic properties of the silicene sheets were affected by not only the defects but also their corrugated structure. Fracture failure of the silicene sheet with defects usually started from the Si–Si bond, which was located at the defect edge. The stretching strain could tune the electronic structure of the silicene sheets. This study demonstrated the defect-sensitive performance of silicene under uniaxial tension and thus helped evaluate and extend the application of this material.