Tunable spin-polarized source by the δ-dopingδ-doping in anisomerous double δ-magnetic-barrierδ-magnetic-barrier nanostructure

•Effects of the δ-dopingδ-doping on electron-spin polarization in a spin filter are investigated.•Electron-spin polarization is dependent greatly on the height and/or position of the δ-dopingδ-doping.•Both magnitude and sign of electron-spin polarization are tunable by the δ-dopingδ-doping.•A structurally tunable spin-polarized source is achieved.

Based on anisomerous double δ-magnetic-barrierδ-magnetic-barrier nanostructure, an electron-spin filter can be formed [M.W. Lu, Appl. Surf. Sci. 252 (2005) 1747]. To structurally manipulate the spin polarization in spin filter, we dope a tunable δ-potentialδ-potential into the device by using modern material growth techniques such as molecular beam epitaxy. It is shown that the degree of electron-spin polarization depends greatly on the height and/or position of the δ-dopingδ-doping. Thus, the device can be used as a tunable spin-polarized source by the δ-dopingδ-doping.