论文标题
部分可观测时空混沌系统的无模型预测
Substrate Effects on Spin Relaxation in Two-Dimensional Dirac Materials with Strong Spin-Orbit Coupling
论文作者
论文摘要
了解二维（2D）材料中底物对旋转动力学的影响和放松的影响对于Spintronics和量子信息应用至关重要。然而，尚不清楚确定底物对自旋松弛的影响的关键因素，特别是对于具有强旋转轨道耦合的材料，尚未得到充分了解。在这里，我们对旋转轨道耦合（SOC）（SOC）进行了第一原理 - 实时密度 - 矩阵动力学模拟，以及对支持/自由式德国人的自旋寿命（一种原型的型德国人）的自旋寿命，一种原型的强度SOC 2D DIRAC材料。我们表明，不同底物对自旋寿命的影响令人惊讶地差异两个数量级。我们发现，底物对$τ_s$的影响与SOC场各向异性的底物诱导的修饰密切相关，后者会改变自旋式散射矩阵元素。我们提出了一个新的电子数量，称为旋转角度$θ^{\ uparrow \ downarrow} $，以表征由Intervalley Spin-Flip散射引起的自旋松弛。我们发现，自旋松弛率与$ \ mathrm {sin}^{2} \ left（θ^{\ uparrow \ downarrow}/2 \ right）$的平均值大致成正比，可以用作控制旋转释放的指导参数。
Understanding substrate effects on spin dynamics and relaxation in two-dimensional (2D) materials is of key importance for spintronics and quantum information applications. However, the key factors that determine the substrate effect on spin relaxation, in particular for materials with strong spin-orbit coupling, have not been well understood. Here we performed first-principles real-time density-matrix dynamics simulations with spin-orbit coupling (SOC) and quantum descriptions of electron-phonon and electron-impurity scattering for the spin lifetimes of supported/free-standing germanene, a prototypical strong SOC 2D Dirac material. We show that the effects of different substrates on spin lifetime can surprisingly differ by two orders of magnitude. We find that substrate effects on $τ_s$ are closely related to substrate-induced modifications of the SOC-field anisotropy, which changes the spin-flip scattering matrix elements. We propose a new electronic quantity, named spin-flip angle $θ^{\uparrow\downarrow}$, to characterize spin relaxation caused by intervalley spin-flip scattering. We find that the spin relaxation rate is approximately proportional to the averaged value of $\mathrm{sin}^{2}\left(θ^{\uparrow\downarrow}/2\right)$, which can be used as a guiding parameter of controlling spin relaxation.
