Light-field assisted spin-polarized transport properties in magnetic-electric barrier structures

Based on the Floquet theory and transfer-matrix method, We investigated the influence of light-field on the spin-polarized transport properties for electrons tunneling through two kinds of magnetic-electric barrier structures (the \begin{document}$\delta$\end{document}-doped magnetic-barrier can be realized in experiments by depositing two ferromagnetic stripes on top and bottom of a semiconductor heterostructure and the light-field can be realized by placing a hemispherical silicon lens on the back surface of the semiconductor substrate). Transport properties result from the interaction of electrons with the light-field by means of photon absorption and emission. It is found that the light-field can greatly affect the transmission probabilities as well as the corresponding polarizations. The distance between the adjacent peaks and the number of the transport peaks can be controlled by adjusting the frequency and the amplitude of the light-field, respectively. It is shown that a significant spin-polarization effect can be induced by such light-field in the kind of antisymmetric magnetic barrier structure ( \begin{document}$B_{1}=-B_{2}$\end{document}) and the light-field can greatly change the spin-polarization effect in the kind of symmetric magnetic barrier structure ( \begin{document}$B_{1}=B_{2}$\end{document}). When the frequency of the light-field increases, the spin-polarization shifts toward the low-energy end and gradually increases. These remarkable properties of spin polarization may be beneficial for the devising tunable spin filtering devices.