Electron Transport in Edge-Disordered Graphene Nanoribbons

Ab initio methods are used to study the spin-resolved transport properties of graphene nanoribbons (GNRs) that have both chemical and structural edge disorder. Oxygen edge adsorbates on ideal and protruded ribbons are chosen as representative examples, with the protrusions forming the smallest possible structural disorder consistent with the edge geometry. The impact of the oxygen adsorbate dominates the transport properties of armchair nanoribbons. For zigzag nanoribbons, the transmission properties are markedly affected by the protrusion alone, leading to spin-polarized transport and a smaller perturbation from the oxygen adsorbate. Armchair nanoribbons also exhibit, as a function of their width and the threefold family structure, a repeating pattern related to the existence of the spin polarization and to the variation in the width of the band gap.