▎ 摘　　要

The effective magnetic coupling between magnetic impurities adsorbed on graphene, which is mediated by the itinerant graphene electrons, and its impact on the electrons' spectral density are studied. The magnetic interaction breaks the symmetry between the sublattices, leading to antiferromagnetic order, and a gap for the itinerant electrons develops. Random doping produces a semiconductor but if all or most of the impurities are localized in the same sublattice the spin degeneracy can be lifted and a spin-polarized semiconductor induced.