An atomistic model for predicting charge distribution in hexagonal boron nitride

We propose an atomistic charge-dipole model for predicting the distribution of doping charge in hexagonal boron nitride (h-BN), based on parameterization using density functional theory calculations. Using this model, we predict the charge distribution in h-BN nanosheets of different geometries. A significant nanometer-size effect is revealed: The charge enhancement effect on the zigzag edge is more significant than that on the armchair one, while the charge enhancement factor increases sublinearly with the dimension of rectangular monolayer sheets or the number of layers for multilayer nanoribbons. This model is also parameterized for predicting the effect of the external electric field on the distribution of intrinsic charge. It can be integrated into molecular simulations in combination with classical force fields for predicting electrostatic effects such as electrostriction, electrodeflection, piezoelectricity and flexoelectricity in finite-size two-dimensional nanostructures.