Production of spin-semiconducting zigzag graphene nanoribbons by constructing asymmetric notch on graphene edges

The electronic and magnetic properties of zigzag graphene nanoribbons with asymmetric notches along their edges are investigated by first principle density functional theory calculations. It is found that the electronic and magnetic properties of the asymmetrically-notched graphene nanoribbons are closely related with the depth of notches, but weakly dependent on the length of notches. As the relative depth of notch increases, the energy level of spin-up and spin-down becomes greatly shifted, associated with the gradual increase of magnetic momentum. The asymmetric band shift allows the asymmetrically notched graphene nanoribbons to be a spin semiconductor, through which an N- or P-type spin-semiconductor can be obtained by doping B or N atoms.