ABSTRACT
The chemical modifications on the essential properties of graphene nanoribbons could be easily achieved by the alkali surface adsorptions under the active environment, especially for the adatom-induced free carrier density and the diversified spin arrangements. Graphene nanoribbons, with open edges passivated by hydrogen atoms, are adsorbed by alkali atoms on surfaces. The geometric, electronic and magnetic properties are investigated under the different alkali adatoms, concentrations, distributions, widths, and edge structures. In addition to zipping, folding, stacking, scrolling, and edge decoration, the surface adsorption is a very efficient method in diversifying the essential properties of graphene nanoribbons. Alkali adatoms are very suitable for a model study, since only the outmost s-orbital plays a critical role in the active chemical environment. The alkali-atom adsorption can dramatically alter band structures of graphene nanoribbons, especially for the blue shift of the Fermi level. The alkali-adsorbed graphene nanoribbons might have high potentials in nanoelectronic devices.
