Spin polarization of two-dimensional electron gas in a hybrid magnetic-electric barrier

We report on a theoretical study of spin-dependent electron transport in a two-dimensional electron gas (2DEG) modulated by a stripe of ferromagnetic metal under an applied voltage. A general formula of transmission probability for electronic tunneling through this system is obtained. Based on this formula, it is shown that large spin-polarized current can be achieved in such a device. It is also shown that the degree of electron-spin polarization is strongly dependent upon 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. (c) 2005 Elsevier Ltd. All rights reserved.