Spin-dependent transmission of highly polarized electrons through ferromagnet/semiconductor interfaces

用相反极化的圆极化光子辐照激发具有相反自旋极化的极化电子。沉积后，薄膜沿垂直于表面的方向磁化。在室温下测量了具有相反自旋极化的光电流。极化与铁磁性薄膜相同的电子，电流增大，而极化相反的电子，电流减小。在本实验中，使用p-GaAs衬底作为光阴极，因此估计光电子的极化约为30~35%。如果使用具有GaAs/GaAsP应变超晶格的光电阴极，预计会有更清晰的依赖关系，因为极化预计会超过85%。

A spin polarized electron beam emitted from a GaAs photocathode was injected into a thin ferromagnetic layer deposited on the GaAs photocathode and the spin-dependence of the transmission through the ferromagnet/semiconductor interface was investigated. Polarized electrons with opposite spin-polarizations were excited by irradiating with circularly polarized photons of opposite polarity. The ferromagnetic film was a 3nm thick layer of GdTbFe, and a thin oxide layer (2nm) was inserted between the film and the photocathode, which resulted in tunneling transmission of the electrons. After deposition, the film was magnetized in the direction perpendicular to the surface. Photo-currents with opposite spin polarizations were measured at room temperature. For electrons with the same polarization as that of the ferromagnetic films, the current was enhanced, while, on the other hand, the current was reduced in the case of the opposite polarization. In the present experiment, a p-GaAs substrate was used as the photocathode, and therefore the polarization of the photoelectrons was estimated as approximately 30〜35%. If a photocathode with a GaAs/GaAsP strained superlattice is used, a much clearer dependence is anticipated because polarization of more than 85% is expected.