Department of Electrical and Computer Engineering, National University of Singapore, Singapore, 117576, Singapore.
RMIT University, School of Science, Department of Physics, Melbourne, VIC, 3001, Australia.
Nat Commun. 2018 Jun 27;9(1):2492. doi: 10.1038/s41467-018-04939-6.
Charge-to-spin conversion in various materials is the key for the fundamental understanding of spin-orbitronics and efficient magnetization manipulation. Here we report the direct spatial imaging of current-induced spin accumulation at the channel edges of BiSe and BiSbTeSe topological insulators as well as Pt by a scanning photovoltage microscope at room temperature. The spin polarization is along the out-of-plane direction with opposite signs for the two channel edges. The accumulated spin direction reverses sign upon changing the current direction and the detected spin signal shows a linear dependence on the magnitude of currents, indicating that our observed phenomena are current-induced effects. The spin Hall angle of BiSe, BiSbTeSe, and Pt is determined to be 0.0085, 0.0616, and 0.0085, respectively. Our results open up the possibility of optically detecting the current-induced spin accumulations, and thus point towards a better understanding of the interaction between spins and circularly polarized light.
在各种材料中，电荷到自旋的转换是理解自旋轨道电子学和高效磁化操控的关键。在这里，我们通过室温下的扫描光电显微镜报告了在 BiSe 和 BiSbTeSe 拓扑绝缘体以及 Pt 的沟道边缘处电流诱导自旋积累的直接空间成像。自旋极化沿垂直于平面的方向，两个沟道边缘的符号相反。改变电流方向会导致自旋积累方向反转，并且检测到的自旋信号与电流大小呈线性关系，表明我们观察到的现象是电流诱导的效应。BiSe、BiSbTeSe 和 Pt 的自旋霍尔角分别确定为 0.0085、0.0616 和 0.0085。我们的结果为光学检测电流诱导的自旋积累开辟了可能性，从而更好地理解了自旋与圆偏振光之间的相互作用。
