Spin-selective transport through Fe/AlOx/GaAs(100) interfaces under optical spin orientation -: art. no. 134430

Spin-selective transport of optically excited polarized electrons through Fe/GaAs(100) and Fe/AlOx/GaAs(100) interfaces is reported. A visible enhancement in the spin selectivity is observed in the Fe/AlOx/GaAs(100) structure at a forward bias of 0.04 V, while no such feature is seen in the Fe/GaAs(100) structure. The spin selectivity in the Fe/AlOx/GaAs(100) structure has a maximum value which is a factor of 2 larger than that of the Fe/GaAs(100) structure at the same bias of 0.04 V. The effect can be understood in terms of the spin dependent tunneling of electrons through the oxide barrier in the Fe/AlOx/GaAs(100) structure, while its clear bias dependence excludes magnetic circular dichroism as a possible mechanism.