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We theoretically explore to manipulate the electron-spin polarization by a δ-potential in 3-layered semiconductor heterostructure modulated by the Rashba spin-orbit-coupling. An obvious electron-spin polarization effect still exists even if the δ-potential is embedded inside. Both size and sign of the electron-spin polarization can be tuned by changing the weight or position of the δ-potential. Therefore, a controllable spin filter can be obtained for spintronics device applications.

Considering Dresselhaus-type spin–orbit coupling (SOC), we theoretically investigate spin-polarized transport in a 3-layered semiconductor heterostructure, InSb/InxGa1-xAs/GaSb. Adopting improved transfer matrix method to solve Schrodinger equation, electronic transmission coefficient is obtained exactly, and then spin polarization ratio is evaluated. An appreciable electron-spin polarization effect by the Dresselhaus-SOC appears in this layered semiconductor heterostructure. Spin polarization is associated closely with in-plane wave vector, incident direction and SOC strength. In particular, both magnitude and sign of spin polarization are manipulated by strain engineering or an appropriate intermediate-layer. Therefore, such a 3-layered semiconductor heterostructure can serve as a controllable spin filter for spintronics device applications.