Spin filtering and spin separating effects in U-shaped topological insulator devices
Spin filtering and spin separating effects in U-shaped topological insulator devices
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DOI：
10.1063/1.4757411
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发表时间：
2012-10
影响因子：
3.2
通讯作者：
M. Zeng;G. Liang
中科院分区：
文献类型：
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作者：
M. Zeng;G. Liang
利用非平衡格林函数（NEGF）研究了基于二维拓扑绝缘体（2DTI）的u型多终端器件（如HgTe量子阱（HgTe QW））的自旋输运性质。结果表明，该2DTI多端器件可以在没有铁磁电极和外加磁场的情况下作为理想的自旋滤波器工作。电可调自旋极化可以接近100%。此外，该装置可以将具有相反自旋的电子从非极化源重新分配到不同的引线，从而形成一个双功能装置，可以同时作为自旋滤波器和自旋分离器。这些有趣的输运性质可以归因于量子自旋霍尔系统中独特的螺旋边缘态。在弱无序、宽度和偏置电压变化的情况下，u型器件的性能是稳健的，但在强无序和空位的情况下，性能就会下降。通用的能力……
Using non-equilibrium Green's function (NEGF), we investigate spin transport properties of a U-shaped, multi-terminal device based on two-dimensional topological insulator (2DTI), such as HgTe quantum well (HgTe QW). The results show that this 2DTI multi-terminal device can be implemented as a perfect spin filter operating in the absence of ferromagnetic electrodes and external magnetic field. The electrically tunable spin polarization can approach 100%. Moreover, the device can redistribute electrons with opposite spins from an unpolarized source to different leads, resulting in a bifunctional device, which can simultaneously operate as a spin filter and a spin separator. These interesting transport properties can be attributed to the unique helical edge states in a quantum spin Hall system. The performance of the U-shaped device is robust against the weak disorder and the variation in widths and bias voltages, but deteriorates in the presence of the strong disorder and vacancies. The capability of gener...