Abstract

We propose a possible spatial spin filter on a Y-shaped zigzag silicene nanoribbon (ZSNR) junction with different even(odd)-chain electrodes by applying three pumping electric fields. By means of the tight-binding model and Keldysh Green’s function method, we calculate the spin-dependent tunneling currents on the middle–left (M–L) and middle–right (M–R) terminals of Y-shaped ZSNR junction, and find that this spin pump not only can generate a pure spin current and a 100% polarized spin current at a zero bias, but also can spatially separate spin up and spin down currents on its even(odd)-chain M–L(R) terminals. The spatial spin filtering phenomena might come from the combination of the even–odd chain effect and single photon-assisted pumping process. The pumped spin up(down) current and its ON(OFF) transport states on M–L(R) terminal of the Y-shaped ZSNR junction can be modulated by almost all the device’s parameters such as the Fermi level, pumping frequency, spin–orbit coupling, staggered lattice potential and magnetization distribution. We also explore the possible way to close the spatial spin filtering behaviors in the device. Our findings might be useful for producing and separating 100% polarized spin up and down currents on multi-terminal silicene nanodevices.

Graphical abstract

中文翻译：

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Y形之字形硅纳米带结上的奇偶链效应和量子泵浦效应引起的空间自旋滤波器

摘要

我们通过施加三个泵浦电场，在具有不同偶数（奇数）链电极的Y形锯齿形硅纳米带（ZSNR）结上提出了一种可能的空间自旋滤波器。通过紧密结合模型和凯尔迪什格林函数方法，我们计算了Y型ZSNR结的中左（ML）和中右（MR）端子上与自旋有关的隧穿电流，并且发现这种自旋泵不仅可以在零偏压下产生纯自旋电流和100％极化自旋电流，而且还可以在空间上分离其偶数（奇数）链M–L（R）上的自旋向上和向下旋转电流终端。空间自旋滤波现象可能来自奇偶链效应和单光子辅助泵浦过程的结合。Y形ZSNR结的M–L（R）端子上的泵浦的向上旋转（向下）电流及其ON（OFF）传输状态可以通过几乎所有器件的参数进行调制，例如费米能级，泵浦频率，自旋–轨道耦合，交错的晶格势和磁化分布。我们还探索了关闭设备中空间自旋滤波行为的可能方法。我们的发现可能对在多端子硅纳米器件上产生和分离100％的极化自旋向上和向下电流有用。

图形概要