Valley-spin filtering through a nonmagnetic resonant tunneling structure in silicene
Valley-spin filtering through a nonmagnetic resonant tunneling structure in silicene
复制标题
通过硅烯中非磁共振隧道结构的谷自旋过滤
DOI：
10.1088/1361-6463/aac564
复制
发表时间：
2018
期刊：
影响因子：
--
通讯作者：
Xu Xing
中科院分区：
文献类型：
--
作者：
Wu Xiuqiang;Meng Hao;Zhang Haiyang;Bai Yujie;Xu Xing
我们从理论上研究了如何使用散射矩阵方法定制基于硅烯的双共振隧穿结构，即双静电势结构，以产生谷极化和自旋极化滤波。这种方法使我们能够找到简单的散射振幅的解析表达式。结果表明，来自相反自旋和谷的电子的传输表现出完全相反的行为，导致在很宽的传输方向上的谷和自旋过滤。这些方向相关的谷自旋极化行为可以用来选择优先方向沿着，初始未极化的载流子的谷自旋极化可以被强烈增强。我们还发现这种现象是相干效应、静电势和外电场共同作用的结果。特别是当外加电场方向改变时，自旋滤波特性被保留，而谷值滤波特性可以被切换。此外，滤波行为可以方便地通过电子门控控制。因此，本研究结果可提供一种在硅烯中构造谷旋滤波器的全电方法。
We theoretically investigate how a silecene-based nonmagnetic resonant-tunneling structure, ie a double electrostatic potential structure, can be tailored to generate valley-and spin-polarized filtering by using the scattering matrix method. This method allows us to find simple analytical expressions for the scattering amplitudes. It is found that the transmissions of electrons from opposite spin and valley show exactly opposite behaviors, leading to valley and spin filtering in a wide range of transmission directions. These directional-dependent valley-spin polarization behaviors can be used to select preferential directions along which the valley-spin polarization of an initially unpolarized carrier can be strongly enhanced. We also find that this phenomenon arises from the combinations of the coherent effect, electrostatic potential and external electric field. Especially when the direction of the external electric field is changed, the spin filtering properties are contained, while the valley filtering properties can be switched. In addition, the filtering behaviors can be conveniently controlled by electrical gating. Therefore, the results can offer an all-electric method to construct a valley-spin filter in silicene.