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 BC2N, 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 vertical bar graphite and Co vertical bar graphite interfaces to make perfect tunnel junctions or ideal spin injectors with any desired resistance-area product.