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We theoretically explore how to control electron-spin polarization in layered semiconductor nanostructure (LSN) by a δ -potential realized by atomic-layer doping. Due to Rashba spin-orbit coupling, a considerable spin polarization still remains even through a δ -potential is embedded in the LSN. Spin polarization ratio can be controlled by altering weight or position of δ -potential. Based on such an LSN, a structurally-tunable electron-spin filter may be obtained for spintronics device applications. [ABSTRACT FROM AUTHOR]

The spin-dependent electron transport in a two-dimensional electron gas (2DEG) modulated by a stripe of magnetized ferromagnetic metal under an applied voltage was investigated theoretically. It is revealed that highly spin-polarized current can be achieved in this kind of nanosystems. It is also shown that the spin polarity of the electron transport can be switched by adjusting the applied voltage to the stripe in the device. These interesting properties may provide an alternative scheme to spin polarize electrons into semiconductors, and this device may be used as a voltage-tunable spin filter. [ABSTRACT FROM AUTHOR]

We theoretically investigate the spin-dependent transport properties of electrons in realistic magnetic-electric barrier nanostructures, which are produced by the deposition, on top of a heterostructure, of a metallic ferromagnetic stripe with an applied voltage. The degree of the electron-spin polarization is found to be closely associated with this voltage, although the use of applied voltage itself induces no spin polarization effect. As a positive voltage is applied to the stripe the electron-spin polarization shifts towards the low-energy region and increases; it shifts towards the high-energy direction and reduces for a negative applied voltage. These results shown in this work imply that the degree of electron-spin polarization can be tuned by means of an applied voltage on the stripes of system, which may result in a practical voltage-controlled spin filter. [ABSTRACT FROM AUTHOR]