We propose and analyze surface-plasmon-driven electron spin currents in a thin metallic film. The electron gas in the metal follows the transversally rotating electric fields of the surface plasmons (SPs), which leads to a static magnetization gradient. We consider herein SPs in a thin-film insulator-metal-insulator structure and solve the spin diffusion equation in the presence of a magnetization gradient. The results reveal that the SPs at the metal interfaces generate spin currents in the metallic film. For thinner film, the SPs become strongly hybridized, which increases the magnetization gradient and enhances the spin current. We also discuss how the spin current depends on SP wavelength and the spin-diffusion length of the metal. The polarization of the spin current can be controlled by tuning the wavelength of the SPs and/or the spin diffusion length.

中文翻译：

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表面等离子体对薄膜系统中自旋电流的影响

我们提出并分析了金属薄膜中表面等离子体驱动的电子自旋电流。金属中的电子气跟随表面等离子体激元 (SP) 的横向旋转电场，从而导致静态磁​​化梯度。我们在此考虑薄膜绝缘体-金属-绝缘体结构中的 SP，并在存在磁化梯度的情况下求解自旋扩散方程。结果表明，金属界面处的 SP 在金属膜中产生自旋电流。对于较薄的薄膜，SPs 变得强烈杂化，这增加了磁化梯度并增强了自旋电流。我们还讨论了自旋电流如何取决于 SP 波长和金属的自旋扩散长度。