Ultrahigh Conductivity Characteristics Of C5N Graphene Nanoribbons

In this paper,we systematically study the electronic structures and transport properties of the doped graphene nanoribbons by boron atom,nitrogen atom by density function theory combined with nonequilibrium Green's function method.The main results were as follows:We investigated electronic structures and magnetic properties of armchair graphene nanoribbons with chemisorption of atomic boron(B-AGNRs)by performing first principles calculations.Results show that although the previous experiments show that adsorption of B can induce a high net magnetism in graphene,the cutting of such magnetic graphene cannot always result in magnetic ribbons.Only the ribbons in the family of width W=3p+1 is magnetic with a magnetic moment of 1.0?B,which is insensitive to the adsorption positions,ribbon widths,and supercell lengths.While the ribbons in other two families of W=3p,and 3p+2 are nonmagnetic.It is revealed that different from the substitutional B-doping,which leads to the Fermi level shifting to valence band(VB),the B-adsorbing raises up the Fermi level,and the coupled P_z orbitals of the B and nearby C atoms induce a partially-filled energy band(PFEB)present in each ribbon.While the distribution of the PFEB is totally family-dependent.It is well-delocalized as W=3p,or 3p+2,but it is localized as W=3p+1,due to the strong quantum confinement and edge effects.Moreover,the localization can be heavily enhanced by decreasing the ribbon width and increasing the supercell length,due to the enhanced quantum confinement and the weakened interaction between adatoms.The heavily localized PFEB locates right at the Fermi level that is hindered due to the Coulomb repulsion and thus spin-splitting occurs spontaneously,resulting in the magnetic semiconducting characteristics.Our findings provide not only a promising one-dimensional material for developing spin-devices in semiconductor spintronics,but also fundamental insights into the magnetic behavior of the non-metallic atoms adsorbed AGNRsHigh conductivity materials hold great promise in electronics.Here,we report ultrahigh conductivity in graphene nanoribbons with ordered nitrogen-doping(referred to as C5N-GNRs).First-principle results show that the ordered N-doping induces a significant shift-up of Fermi level(?Ef)and gives rise to the well-delocalized partially-filled energy bands presented in the system,which run across the Ef and the crossed times increases as the ribbon widens,resulting in ever-growing high density of states in the system.Remarkably,the conductivity increases with the ribbon widening and reaches ultrahigh(>15 G0)in sub-5-nm wide ribbons with either armchair or zigzag edges.Meanwhile,a simple linear relationship between doing concentration and?Ef is achieved during the evaluation of width-dependence,it is meaningful in understanding and controlling the electronic properties of C5N-GNRs.Our findings open new avenues in realizing high conductivity materials in electronics.