  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 weekly 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 spintronic semiconductor,
through which an N- or P-type spin-semiconductor can be obtained by doping B or
N atoms.
