▎ 摘 要
We show that a bilayer graphene ribbon deposited above a ferromagnetic insulator can behave as a spin-filtering device. The ferromagnetic material induces exchange splitting in the graphene ribbon, and due to the Fano antiresonances occurring in the transmission of the graphene ribbon as a function of ribbon length and energy, it is possible to obtain a net spin current. This happens when an antiresonance for one spin channel coincides with a maximum transmission for the opposite spin. We propose these structures as a means to obtain spin-polarized currents and spin filters in graphene-based systems. (C) 2013 AIP Publishing LLC.