Spin Gapless Semiconductor−Metal−Half-Metal Properties in Nitrogen-Doped Zigzag Graphene Nanoribbons

The geometries, formation energies, and electronic and magnetic properties of N-doping defects, including single atom substitution and pyridine- and pyrrole-like substructures in zigzag graphene nanoribbons (ZGNRs), were investigated by means of spin-unrestricted density functional theory computations. The edge carbon atoms are more easily substituted with N atoms, and three-nitrogen vacancy (3NV) defect and four-nitrogen divacancy (4ND) defect also prefer the ribbon edge. Single N atom substitution and pyridine- and pyrrole-like N-doping defects can all break the degeneracy of the spin polarization of pristine ZGNRs. One single N atom substitution makes the antiferromagnetic semiconducting ZGNRs into spin gapless semiconductors, while double edge substitution transforms N-doped graphenes into metals. Pyridine- and pyrrole-like N-doping defects make ZGNRs into half-metals or spin gapless semiconductors. These results suggest the potential applications of N-doped ZGNRs in nanoelectronics.