标题： 从第一性原理研究时空自旋输运 显示英文标题

标题： Spatio-temporal spin transport from first principles

摘要： 我们引入了一个计算框架，用于在Wigner函数形式化下从头计算密度矩阵传输，以预测量子力学的自旋等自由度在长时间和长距离尺度上的传输。 该框架促进了从第一性原理出发的自旋动力学和传输模拟，同时考虑了器件长度尺度下的电子-声子散射。 我们通过这一框架来阐明各种自旋轨道场分布（如Rashba和持续自旋螺旋）对几种材料中相干自旋传输的影响。 以石墨烯在电场下的情况为例，我们展示了如何用它来说明电子-声子散射对非相干传输的影响，并展示了传输如何随散射强度的变化而变化。 我们确定了三种不同的非相干自旋传输区域，分别对应于自由感应衰减、Dyakonov-Perel和Elliott-Yafet自旋弛豫区域。 特别是，我们表明，在Dyakonov-Perel区域内，自旋扩散长度对散射强度不敏感。 显示英文摘要

摘要： We introduce a computational framework for first-principles density matrix transport within the Wigner function formalism to predict transport of quantum-mechanical degrees of freedom such as spin over long time and length scales. This framework facilitates simulation of spin dynamics and transport from first principles, while accounting for electron-phonon scattering at device length scales. We demonstrate this framework to elucidate the impact of various spin-orbit field profiles, such as Rashba and persistent spin helix, on coherent spin transport in several materials. Using graphene under an electric field as an example to illustrate the impact of electron-phonon scattering on incoherent transport, we show how the transport changes with the strength of scattering. We identify three distinct regimes of incoherent spin transport corresponding to the free induction decay, Dyakonov-Perel and Elliott-Yafet regimes of spin relaxation. In particular, we show that the spin diffusion length is insensitive to the strength of scattering within the Dyakonov-Perel regime.