Watts J D, Batley J T, Rabideau N A, Hoch J P, O'Brien L, Crowell P A, Leighton C
School of Physics and Astronomy, University of Minnesota, Minneapolis, Minnesota 55455, USA.
Department of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, Minnesota 55455, USA.
Phys Rev Lett. 2022 May 20;128(20):207201. doi: 10.1103/PhysRevLett.128.207201.
The Elliott-Yafet theory of spin relaxation in nonmagnetic metals predicts proportionality between spin and momentum relaxation times for scattering centers such as phonons. Here, we test this theory in Al nanowires over a very large thickness range (8.5-300 nm), finding that the Elliott-Yafet proportionality "constant" for phonon scattering in fact exhibits a large, unanticipated finite-size effect. Supported by analytical and numerical modeling, we explain this via strong phonon-induced spin relaxation at surfaces and interfaces, driven in particular by enhanced spin-orbit coupling.
非磁性金属中自旋弛豫的埃利奥特 - 亚费特理论预测，对于诸如声子等散射中心，自旋弛豫时间与动量弛豫时间成正比。在此，我们在非常大的厚度范围（8.5 - 300纳米）内对铝纳米线中的该理论进行了测试，发现声子散射的埃利奥特 - 亚费特比例“常数”实际上呈现出一种巨大的、意想不到的有限尺寸效应。在解析和数值模拟的支持下，我们通过表面和界面处由声子强烈诱导的自旋弛豫来解释这一现象，这种自旋弛豫尤其由增强的自旋 - 轨道耦合驱动。
