Tuning magnetism in graphene nanoribbons via strain and adatoms

We investigate the impact of strain and adsorbed H adatoms on the magnetic properties of zigzag graphene nanoribbons (ZGNRs) using a combination of tight-binding and density functional theory methods for both ferromagnetic (FM) and antiferromagnetic (AFM) edge configurations. We focus on the metallic FM edge configuration of the ZGNRs to better exploit the tuning of its properties. We find that the magnetic configuration of H adatoms is strongly influenced by the edges, with an AFM coupling between edges and the H adatom. In fact, the magnetic spatial pattern of the H adatom differs from that found in graphene due to this edge coupling. Importantly, we find robust discrete plateaus of integer magnetic moment as strain is varied in the defected ZGNRs, which we relate to changes in the band structure, namely, a half-metallic character or the opening of a gap. This behavior can be of interest for magnetic applications of carbon-based nanostructures.