Chen Jen-Ru, Tse Pok Lam, Krivorotov Ilya N, Lu Jia G
Department of Physics and Astronomy, University of California, Irvine, California 92697, USA.
Nanoscale. 2020 Nov 26;12(45):22958-22962. doi: 10.1039/d0nr06590k.
The momentum and spin of charge carriers in the topological insulators are constrained to be perpendicular to each other due to the strong spin-orbit coupling. We have investigated this unique spin-momentum locking property in Sb2Te3 topological insulator nanowires by injecting spin-polarized electrons through magnetic tunnel junction electrodes. Non-local voltage measurements exhibit an asymmetry with respect to the magnetic field applied perpendicular to the nanowire channel, which is remarkably different from that of a non-local measurement in a channel that lacks spin-momentum locking. In stark contrast to conventional non-local spin valves, simultaneous reversal of magnetic moments of all magnetic contacts to the Sb2Te3 nanowire alters the non-local voltage. This unusual asymmetry is a clear signature of the spin-momentum locking in the Sb2Te3 nanowire surface states.
由于强自旋轨道耦合，拓扑绝缘体中电荷载流子的动量和自旋被限制为相互垂直。我们通过磁隧道结电极注入自旋极化电子，研究了Sb2Te3拓扑绝缘体纳米线中这种独特的自旋动量锁定特性。非局域电压测量显示出相对于垂直于纳米线通道施加的磁场的不对称性，这与缺乏自旋动量锁定的通道中的非局域测量有显著不同。与传统的非局域自旋阀形成鲜明对比的是，与Sb2Te3纳米线所有磁接触的磁矩同时反转会改变非局域电压。这种不寻常的不对称性是Sb2Te3纳米线表面态中自旋动量锁定的明显标志。
