Ni(111)|graphene|h-BN junctions as ideal spin injectors

Deposition of graphene on top of hexagonal boron nitride (h-BN) was very recently demonstrated, while graphene is now routinely grown on Ni. Because the in-plane lattice constants of graphite, h-BN, graphitelike BC ₂ N, and of the close-packed surfaces of Co, Ni, and Cu match almost perfectly, it should be possible to prepare ideal interfaces between these materials which are, respectively, a semimetal, an insulator, a semiconductor, and ferromagnetic and nonmagnetic metals. Using parameter-free energy minimization and electronic transport calculations, we show how h-BN can be combined with the perfect spin filtering property of Ni|graphite and Co|graphite interfaces to make perfect tunnel junctions or ideal spin injectors with any desired resistance-area product.