Rashba自旋轨道耦合作用下电荷流散粒噪声与自旋极化的关系研究

根据存在自旋轨道耦合时基于散射理论的电流表达式和散粒噪声表达式，并利用自旋密度矩阵推导出沿自旋量子化坐标的自旋极化率表达式.解析计算了单通道的情况，发现自旋极化率和电荷流散粒噪声无关.由于多通道解析推导的困难，使用非平衡格林函数技巧，数值计算了包含自旋轨道耦合效应的纯净二维电子气的多通道情况.分别改变偏压、自旋轨道耦合系数、导体长度，研究了这三种不同条件下的自旋极化率与电荷流散粒噪声Fano因子的相关性.两者的相关性表明，相关性定量关系的建立可能为自旋极化的全电学检测提供新思路. 关键词： 散粒噪声 自旋极化 Rashba自旋轨道耦合 散射矩阵

Relation between charge shot noise and spin polarization governed by Rashba spin orbit interaction

When the Rashba spin orbit interaction is available， the spin polarization along the spin quantization axis is derived form the spin density matrix， with the help of current and shot noise formula based on the scattering theory. Charge shot noise and spin polarization are derived in the case of single channel， and there exists no relation between them. Due to the difficulty in derivation in multichannel， at least two channels， the nonequilibrium Greens function technique is used to numerically compute the scattering matrix， the current and the shot noise of clean two-dimensional electron gas governed by the spin orbit coupling effect. The relation between charge shot noise and spin polarization is investigated separately in conditions of variable bias， spin orbit interaction coefficient and conductor length， which demonstrates that the establishment of quantitive relation may provide a new way to realize all-electrical detection of spin polarization.