三节点一维相互作用链的非平衡自旋传输特性及其解析公式

Nonequilibrium spin transport properties of three site one-dimensional chain system with electronic interactions and their analytic formulas

为理解和处理介观系统中电子自旋传输的基础理论问题,对典型的三节点一维相互作用链模型的非平衡自旋传输特性进行了理论分析以及解析公式的推导。首先严密推导出半填充假设下模型的基态并计算了各节点的初始电荷。然后基于Keldysh非平衡格林函数理论,阐述了其基本理论方法并推导了考虑电子间库仑相互作用及Hartree-Fock近似条件下模型的非平衡自旋传输特性(非平衡微分自旋电导、自旋传输电流和自旋电荷分布)的主要解析公式。最后在典型参数条件下使用这些初始电荷和解析公式对相关模型的非平衡自旋传输特性进行了自洽计算,并给出相应的物理解释,验证了公式的正确性和有效性。

In order to understand and deal with the basic theoretical problems of the electron spin transport in mesoscopic systems,nonequilibrium spin transport properties of typical three site one-dimensional(1D)quantum chain system with electronic interactions are analyzed and the corresponding analytic formulas are deduced.Firstly,the initial charge on each site of the chain is calculated from the exactly derived ground state under the half-filling assumption.Then,based on Keldysh formalism,the basic theoretical methods are described in detail,and the main analytic formulas of the nonequilibrium spin transport properties(differential spin conductance,spin transport current and electronic charge distribution,etc.)of the 1D chain systems are derived considering Hartree-Fock approximation and Coulomb electronic interaction.Both the cases,namely,the scattering process considering the Coulomb repulsion force between the spin-up and spin-down electrons and the scattering process considering the spin-spin interaction due to spin degree of freedom,are considered.Finally,under the conditions of typical parameters,the initial charges and calculating formulas are used to calculate the nonequilibrium spin transport properties of the chain system self-consistently,and the corresponding physical interpretations of the numerical calculation data are provided,which verifies the correctness and validity of the formulas.