Metal-adsorbed graphene nanoribbons

The metal atoms, the alkali ones excepted, might provide the multiple outermost orbitals for the multi-orbital hybridizations with the out-of-plane $π$ bondings on the honeycomb lattice. This will dominate the fundamental properties of Al-, Ti- and Bi-adsorbed graphene nanoribbons, in which they are explored thoroughly by using the first-principles calculations. The principle focuses are the adatom-dependent binding energies, the adatom-carbon lengths, the optimal position, the maximum adatom concentrations, the free electron density transferred per adatom, the adatom-related valence and conduction bands, the various van Hove singularities in DOSs, the transition-metal-induced magnetic properties, and the significant competitions of the zigzag edge carbons and the metal/transition metal adatoms in spin configurations. The distinct chemical bondings are clearly identified from three kinds of metal adatoms under the delicate physical quantities. The important differences between Al-/Ti-/Bi- and alkali-adsorbed graphene nanoribbons will be discussed in detail, covering band structures, relation of conduction electron density and adatom concentration, spatial charge distributions, orbital-decomposed DOSs, and magnetic configurations $\&$ moments.