Electronic structure and bonding in hexagonal boron nitride

The bonding, cohesive, and electronic properties of hexagonal boron nitride were studied using density functional theory calculations. The properties of this system were calculated using three different exchange-correlation functionals (local density approximation and two forms of the generalized gradient approximation) to determine their relative predictive abilities for this system. In-plane and interplanar bonding was examined using band diagrams, the density of states, and the electron localization function. Different stackings, or arrangements of one basal plane with respect to another, were examined to determine how the bonding and electronic structure changed between different stackings. Calculated band gaps were in the 2.9-4.5 eV range and predominantly indirect, regardless of stacking or the exchange-correlation functional used. The calculated band gaps are in the low range of experimental band gap values, and do not explain the large range of experimental values.