Spin-filter effect by introducing an edge vacancy on armchair graphene nanoribbons with oxygen termination

We studied the spin transport properties of an oxygen-terminated armchair graphene nanoribbon (O-AGNR) with a single edge vacancy via an ab-initio calculation based on density functional theory combined with the nonequilibrium Green's function technique. We found that spin-filtering occurs regardless of the ribbon width by introducing an edge vacancy on one edge side of the O-AGNR because the four energy bands mainly consisted of the oxygen p orbital, such that the up-spin states were localized on one edge side and the down-spin states were on the other edge side. Moreover, we showed that the absolute value of spin-filtering efficiency reached ∼1.00 at certain values of the chemical potential; additionally, the direction of spin polarization can be switched by controlling the chemical potential. These results suggest that O-AGNRs have potential applications in spintronics devices.