Based on transfer-matrix method, we investigate the effect of bias on electron-spin polarization in the spin filter, which can be experimentally realized by depositing two ferromagnetic (FM)strips and a Schottky metal (SM) stripe in parallel configuration on top of the heterostructure. We ?nd that both magnitude and sign of the electron-spin polarization are sensitive to the applied bias in this spin filter, which can result in a bias-tunable spin ?lter.
