Deformation mechanism and minimum energy path in Silicon–graphite composites with lattice defects

Abstract

Edge-on atomic layers in layered solids undergo buckling, which creates a structure referred to as a “ripplocation.” A collective set of multiple ripplocations is referred to as a “ripplocation boundary.” In this study, in order to investigate the impact of lattice defects on ripplocation, we investigate the buckling deformation of graphene with lattice defects under confinement. To this end, we conducted confined uniaxial compression simulations by placing graphene sheets with various lattice defects between silicon atomic layers. Different types of lattice defects affect the mechanical properties of graphene, the results show that Young's modulus of graphene with the (1,0)_5 dislocation pair was the maximum at 494.6 GPa, whereas the Young's modulus of the (1,2)_10 dislocation pair was the minimum at 309.5 GPa. In addition, we employed a differential geometry method to study the out-of-plane deformation of a single-layer graphene system. Further, we used the nudged elastic band method for various types of lattice defects in graphene to uncover the minimum transition pathways, activation energy required to move from the (1, 0) dislocation pair to the (1, 1) pair is 44.916 eV. In particular, the results indicate that graphene with lattice defects exhibit kink deformation after buckling compared to that of perfect graphene. Our study not only explores the deformation of ripplocations and kink boundaries in layered solids but also provides a more comprehensive description influencing lattice defects on the nucleation mechanism and mechanical changes of ripplocations in graphene.