Structural properties and charge distribution in graphene/BN heterostructures

We investigate the structural properties of heterostructures comprising bilayer graphene covered with hexagonal boron nitride (hBN) using density functional theory including non-local van der Waals corrections. Both AA ′ and AB stacking configurations of hBN are examined. We find that the in-plane lattice parameter of the heterostructure exhibits a linear dependence on the reciprocal of the number of hBN layers, which can be understood within a continuum strain-sharing model. Beyond a critical thickness of approximately four hBN layers, the graphene–BN interface separation and the in-plane components of the macroscopic stress are strongly reduced. This behavior is associated with a redistribution between elastic and van der Waals energy contributions driven by interfacial charge transfer. Our results highlight the interplay between strain accommodation, interlayer interaction, and charge redistribution in graphene/hBN heterostructures.