Bonding of hexagonal BN to transition metal surfaces:: An ab initio density-functional theory study

Hexagonal h-BN/metal interfaces for different 3d, 4d, and 5d metals are studied in terms of ab initio density functional theory. The trends across the periodic table of the bonding of h-BN to the metal surfaces are discussed. We show that the binding energy between h-BN and the metal surface decreases with the filling of the d shell and is largest for 4d elements. For all studied metals the N atom is repelled from the metal surface, whereas the B atom is attracted to it. The strength of attraction/repulsion of B and N atoms depends on their position relative to the underlying metal atoms, and only when N sits on-top of the metal and B occupies fcc or hcp hollow sites the B-attraction dominates the N repulsion and h-BN is bound to the surface. The structure of the h-BN/metal interface is a result of the balance between these forces and the lattice mismatch.