Ferroelectric polarization of graphene/h-BN bilayer of different stacking orders

In recent years, two-dimensional van der Waals materials including graphene and hexagonal boron nitride (h-BN) have attracted extensive interest from researchers of many fields. In this paper, the polarization properties of graphene/h-BN van der Waals heterostructures with different stacking orders are explored by first-principle calculations. Notably, the direction of graphene/h-BN heterostructure polarization can be flipped (from AB stacking to BA stacking) by changing its stacking method. According to differential charge density analysis, the interlayer charge redistribution is the main reason driving the polarization flip. Also, we find that the polarization increases with compression of the layers and tensile strain of the lattice. In addition, we investigated the effect of the twisting angle on the polarization. The results show that polarization flip occurs during interlayer rotation and, interestingly, the magnitude and direction of polarization remain constant over a range of twist angles. The results of this study provide insight into the polarization properties of graphene/h-BN heterostructures, which is important for their potential applications in electronic devices.