Perfect spin filtering effect and negative differential behavior in phosphorus-doped zigzag graphene nanoribbons

On the basis of the density functional theory combined with the Keldysh nonequilibrium Green's function method, we investigate the spin-dependent transport properties of single-edge phosphorus-doped ZGNR systems with different widths. The results show a perfect spin filtering effect reaching 100% at a wide bias range in both parallel (P) and antiparallel (AP) spin configurations for all systems, especially for 6-ZGNR-P system. Instructively, for the AP spin configuration, the spin down current of the 4-ZGNR-P system exhibits a negative differential effect. By analyzing the transmission spectrum and the spin-resolved band structures of the electrodes, we elucidate the mechanism for these peculiar properties. Our findings provide a new way to produce multifunctional spintronic devices based on phosphorus-doped zigzag graphene nanoribbons.