Structural and magnetic properties of Fe-membranes embedded in hexagonal graphene nanoholes

Abstract The structure and magnetism of Fe-doped hexagonal graphene nanoholes (h-GNHs) were studied on the basis of density-functional theory. The nonzero magnetic moment of carbon in zigzag edge can be greatly reduced in Fe-doped h-GNHs due to the local C Fe interaction. The reduced magnetic moment is almost zero, and its direction is opposite to that of iron atoms. Therefore, Fe-adsorption may be used to destroy the spin polarization of graphene zigzag edge. In Fe-doped h-GNHs, iron atom would prefer to adsorb on graphene armchair edge and form five-member (1Fe + 4C) ring. In stable Fe-doped h-GNHs, the bond length of C Fe is about 1.9 A. And in the most stable Fe-membrane embedded h-GNH with the largest binding energy, the average Fe Fe bond length is about 2.36 A. Besides, the mean magnetic moment induced by iron atoms changes greatly from 1.45 μ B per iron atom to 3.46 μ B per iron atom in Fe-doped h-GNHs. The magnetism of iron seems to be sophisticated. It is related to the type of graphene edge, the size of GNH and the number of iron atoms.