Spin and band-gap engineering in doped graphene nanoribbons

We investigate electronic and magnetic properties of graphene nanoribbons whose edges are doped by s -, p -, and d -type atoms. The edges of the ribbon are chemically active and can accommodate appropriate dopants to obtain different electronic and magnetic properties, all with the same geometrical structure of the ribbon. Dopings by Mg and B turn the semiconducting armchair ribbon into a metal, while Fe and Mn change it into a ferromagnet with a large magnetic moment. Doping of zigzag ribbon and implications for transport characteristics are also discussed. Our results suggest that the present structures are suitable for nanoelectronic and spintronic applications.