Wang An-Qi, Xiang Peng-Zhan, Ye Xing-Guo, Zheng Wen-Zhuang, Yu Dapeng, Liao Zhi-Min
State Key Laboratory for Mesoscopic Physics and Frontiers Science Center for Nano-optoelectronics, School of Physics, Peking University, Beijing 100871, China.
Academy for Advanced Interdisciplinary Studies, Peking University, Beijing 100871, China.
Nano Lett. 2021 Mar 10;21(5):2026-2032. doi: 10.1021/acs.nanolett.0c04592. Epub 2021 Feb 19.
Topological materials that possess spin-momentum locked surface states provide an ideal platform to manipulate the quantum spin states by electrical means. However, an antisymmetric magnetoresistance (MR) superimposed on the spin-polarized transport signals is usually observed in the spin potentiometric measurements of topological materials, rendering more power loss and reduced signal-to-noise ratio. Here we reveal the mechanism of surface-bulk interaction for the observed antisymmetric linear MR in the spin transport of Dirac semimetal CdAs nanoplates. The antisymmetric linear MR can be eliminated through sample surface modifications. As a consequence, clean signals of charge current induced spin-polarized transport are observed, robust up to room temperature. The purification of spin signals can be attributed to the isolation of surface and bulk transport channels via forming a charge depletion layer with surface modifications. This surface engineering strategy should be valuable for high-performance spintronic devices on topological materials.
具有自旋动量锁定表面态的拓扑材料为通过电学手段操纵量子自旋态提供了一个理想平台。然而，在拓扑材料的自旋电位测量中，通常会观察到叠加在自旋极化传输信号上的反对称磁电阻（MR），这会导致更多的功率损耗并降低信噪比。在此，我们揭示了狄拉克半金属CdAs纳米板自旋输运中观察到的反对称线性MR的表面-体相互作用机制。通过样品表面修饰可以消除反对称线性MR。结果，观察到了电荷电流诱导的自旋极化传输的纯净信号，该信号在室温下都很稳定。自旋信号的纯化可归因于通过表面修饰形成电荷耗尽层来隔离表面和体传输通道。这种表面工程策略对于基于拓扑材料的高性能自旋电子器件应该是有价值的。
