Size and temperature effect on the mechanical properties of graphene/hexagonal boron nitride van der Waals heterostructure

In this paper, mechanical properties of graphene/hexagonal boron nitride (G/h-BN) van der Waals (vdW) heterostructure with various sizes and at different temperatures are investigated by performing molecular dynamics simulations. Furthermore, the effect of vertical vdW interactions on the Young's modulus of substrate materials is discussed. We find that mechanical performances of G/h-BN heterostructure are significant dependent on sizes and temperatures, and double-elastic deformation as well as enhancement of tensile modulus is observed because of vdW interactions. Due to vertical constraint, the double-elastic deformation of graphene substrate takes place at 300 K. Additionally, the out-of-plane displacements become smaller thus the Young's modulus of substrate is enhanced. It is also discovered that there is pre-stress in graphene layer and h-BN layer without tensile loading. The study provides a theoretical basis for the performance and application of G/h-BN heterostructure.