Structural, magnetic, and electronic properties of Nin and Fen nanostructures (n=1-4 ) adsorbed on zigzag graphene nanoribbons

Abstract

Extensive ab initio density-functional calculations were performed to investigate the structural, magnetic, and electronic properties of systems comprising Nin and Fen nanostructures (n=1-4) adsorbed on hydrogen-passivated zigzag graphene nanoribbons (GNRs). Both Ni and Fe atoms were most strongly bound at GNR edge sites and neither altered whether the GNR was metallic or semiconducting. However, Nin nanostructures were more strongly bound than Fen nanostructures, and their atoms had much smaller spin magnetic moments; Nin /GNR systems, like the pristine GNR, always had lowest energy with antiparallel edge spins, whereas among Fen /GNR systems this was only found for one- or two-atom adstructures at subedge or near-subedge atop sites; and zigzag Ni3 and Ni4 chains placed at GNR hole sites retained close contact with the GNR upon relaxation, whereas the analogous Fe chains adopted geometries similar to those of free-standing Fe clusters, with one or more atoms lifted away from the GNR. © 2010 The American Physical Society.