Using the transfer matrix method, the valley- and spin-dependent transport properties in a silicene velocity superlattice under extrinsic Rashba spin-orbit coupling, are theoretically investigated. Silicene velocity superlattice includes the silicene sheet, in which the electrostatic potential and the Fermi velocity vary in space. It was found that through adjusting the Fermi velocity, number of velocity barriers and Rashba spin-orbit interaction, the transmission probability, with and without the spin-flip can be controlled. The results show that increasing the Fermi velocity results in the reduction and enhancement of the oscillation amplitude and oscillation period of the spin-dependent conductance, respectively. Specifically, in the case of Fermi velocity ratio (the Fermi velocity inside barriers over the Fermi velocity outside barriers) being smaller than one, fully valley polarized current can be observed. However, when the Fermi velocity ratio exceeds one, increasing the Fermi velocity leads to the decrement of valley polarization. Furthermore, the spin polarization is controllable via the Fermi velocity ratio.

使用传递矩阵方法，理论上研究了外在Rashba自旋-轨道耦合作用下硅质速度超晶格中谷和自旋相关的输运性质。硅速度超晶格包括硅片，其中静电势和费米速度在空间中变化。研究发现，通过调节费米速度，速度障碍的数量和Rashba自旋轨道相互作用，可以控制有无自旋翻转的传输概率。结果表明，提高费米速度会分别导致自旋相关电导的振幅和振荡周期的减小和增强。特别，在费米速度比（势垒内部的费米速度超过势垒外部的费米速度）小于1的情况下，可以观察到完全谷底极化电流。但是，当费米速度比超过1时，费米速度的增加会导致波谷极化的减小。此外，可以通过费米速度比来控制自旋极化。