  The interlayer sliding energy landscape of hexagonal boron nitride (h-BN) is
investigated via a van der Waals corrected density functional theory approach.
It is found that the main role of the van der Waals forces is to "anchor" the
layers at a fixed distance, whereas the electrostatic forces dictate the
optimal stacking mode and the interlayer sliding energy. A nearly free-sliding
path is identified, along which bandgap modulations of ~0.6 eV are obtained. We
propose a simple geometrical model that quantifies the registry matching
between the layers and captures the essence of the corrugated h-BN interlayer
energy landscape. The simplicity of this phenomenological model opens the way
to the modeling of complex layered structures, such as carbon and boron nitride
nanotubes.
