Tunability of magnetic anisotropy of Co on two-dimensional materials by tetrahedral bonding

Pairing of pi electronic state structures with functional or metallic atoms makes them possible to engineer physical and chemical properties. Herein, we predict the reorientation of magnetization of Co on hexagonal BN (h-BN) and graphene multilayers. The driving mechanism is the formation of the tetrahedral bonding between sp(3) and d orbitals at the interface. More specifically, the intrinsic pi bonding of h-BN and graphene is transformed to sp(3) as a result of strong hybridization with metallic d(z2) orbital. The different features of these two tetrahedral bondings, sp(2) and sp(3), are well manifested in charge density and density of states in the vicinity of the interface, along with associated band structure near the (K) over bar valley. Our findings provide an approach to tailoring magnetism by means of degree of the interlayer hybrid bonds in two-dimensional layered materials.