First-Principles Study of Stacking Type Influences on the Nature of the Band Gap for 2D and 3D h-BN Structures

Various interesting electronic and optical properties can be derived through manipulation of the stacking type of layered materials. In particular, h-BN is of interest because the two-atom-type structure reduces its crystal symmetry compared to graphene and opens up a sizable gap. By engineering the stacking type of h-BN structures, the nature and magnitude of the band gap can be adjusted. Differences in the stacking layers shift the locations of the valence band maximum and conduction band minimum, which may lead to a direct or indirect band gap. We used first-principles calculations based on density functional theory and many-body perturbation theory to investigate the influence of different stacking sequences on the nature and magnitude of the band gap in bulk and few-layer structures of h-BN, including both ordered and randomly-stacked layered structures. Our results establish the connection between the microscopic atomic structure to the character and magnitude of the gap.