Controllable electron-spin polarization by <i>δ</i> -doping in a hybrid ferromagnet and semiconductor nanostructure

Abstract

By using modern materials growth techniques such as molecular beam epitaxy, a tunable δ-potential can be intentionally doped into semiconductor nanostructures. In this work, we theoretically investigate modulation of electron-spin polarization by such a δ-doping in a hybrid ferromagnet and semiconductor nanostructure, where a nanosized ferromagnetic stripe with horizontal magnetization is deposited on top of a semiconductor heterostructure. It is shown that this nanosystem possesses a considerable spin polarization effect due to breaking the intrinsic symmetry by the δ-doping. It is also shown that both magnitude and sign of spin polarization vary dramatically with the height and/or position of the δ-doping. These interesting properties may provide an alternative scheme to achieve a controllable spin-polarized source, and this nanostructure may serve as a structurally tunable spin filter.