Spin filtering in a magnetic nanostructure with the δ-doping

With the help of the transfer-matrix method, the spin-dependent electron transport in a magnetic nanostructure is theoretically investigated. It is found that the obvious spin filtering appears and the large spin-polarized current can be achieved in such a nanostructure with a δ-doping, although the average magnetic field of the structure is zero. These interesting features may provide an alternative scheme to spin-polarize electrons into semiconductors, and this device may be used as a spin filter.