Mechanical properties of a G/h-BN heterobilayer nanosheets coupled by interlayer sp bonds and defects

The mechanical properties of graphene/hexagonal boron nitride (G/h-BN) heterobilayer nanosheets coupled by interlayer sp bonds and defects have been investigated by using the molecular dynamics (MD) simulation. For this purpose, interlayer sp bonds and two kinds of geometric imperfection (including rhombus and square nanopore) are formed in the G/h-BN heterobilayer nanosheets. The effects of adding the nanopore diameter, interlayer sp bonds fraction, and the influence of different position of geometric imperfection in heterobilayer nanostructure on mechanical properties have been investigated. The result shows that when sp bonds and nanopore coexist, the mechanical properties of defective graphene layer are higher than that of defective hexagonal boron nitride (h-BN) layer. Meanwhile, the negative effect of rhomboid nanohole on mechanical properties of heterostructure is weaker than that of square nanohole. It is observed that that interlayer sp bonds have greatest influence on the fracture strain of G/h-BN heterobilayer nanostructure, followed by fracture stress, and finally Young's modulus. Another important point is that interlayer sp bonds can be regarded as a special defect, and its value seems to outweigh the intrinsic defects.