▎ 摘　　要

We studied magnetism in bilayer and multilayer zigzag graphene nanoribbons (ZGNRs) through first-principles density functional theory calculations. We found that the magnetic ground state of bilayer ZGNRs is the C-type antiferromagnetic (AFM) state, which is the AFM order between intraplane-edge carbon atoms and ferromagnetic (FM) order between interplane edge carbon atoms. In the cases of infinitely stacked multilayer ZGNRs, i.e., zigzag graphite nanoribbons, the C-type AFM state is also the most stable. By carrier doping, we found that the magnetic ground state changed from the C-AFM state to the FM state and, thus, realized two-dimensional FM surface (edge) states of graphite with a metallic conductivity. (C) 2014 AIP Publishing LLC.