Quantum anomalous Hall effect in graphene coupled to skyrmions

Skyrmions are topologically protected spin textures, characterized by a topological winding number N, that occur spontaneously in some magnetic materials. Recent experiments have demonstrated the capability to grow graphene on top Fe/lr, a system that exhibits a two-dimensional skyrmion lattice. Here we show that a weak exchange coupling between the Dirac electrons in graphene and a two-dimensional skyrmion lattice with N=+ or -1 drives graphene into a quantum anomalous Hall phase, with a band gap in bulk, a Chern number C=2N, and chiral edge states with perfect quantization of conductance G=2Ne2h. Our findings imply that the topological properties of the skyrmion lattice can be imprinted in the Dirac electrons of graphene.