Spin filter effects in zigzag-edge graphene nanoribbons with symmetric and asymmetric edge hydrogenations

Using the non-equilibrium Green’s function method combined with the density functional theory, we investigate the magnetism and spin-dependent transport properties of symmetric and asymmetric zigzag–edged graphene nanoribbons (ZGNRs) passivated by monohydrogenation with [1, −1] magnetism configuration. The symmetric model H–6ZGNR–H shows a dual spin filter effect, but asymmetric H–5ZGNR–H behaves as a conductor with linear current–voltage relationships. We also investigate the magnetism and spin-dependent transport properties of H2–ZGNR–H with asymmetric edge hydrogenations, the perfect dual spin filtering effect is observed in both H2–5ZGNR–H and H2–6ZGNR–H. The transmission pathways and PDOS demonstrate that the edge of C-H2 bonds have important effects on the magnetism and spin-dependent transport properties as compared with the edge of C–H bonds.