Rashba自旋轨道耦合对电子自旋磁化率的影响  

The Effect of Rashba Spin-Orbital Coupling on Electronic Spin Susceptibility

作　　者：张成 李铭[1] ZHANG Cheng;LI Ming(Laboratory of Quantum Engineering and Quantum Materials∥School of Physics and Telecommunication Engineering, South China Normal University, Guangzhou 510006, China)

机构地区：[1]广东省量子调控工程与材料重点实验室/华南师范大学物理与电信工程学院,广州510006

出　　处：《华南师范大学学报（自然科学版）》2020年第5期26-30,共5页Journal of South China Normal University(Natural Science Edition)

基　　金：国家自然科学基金项目(51972122)。

摘　　要：研究了哈伯德强关联系统中,Rashba自旋轨道耦合(R-SOC)对二维正方晶格的自旋磁化率的影响.在线性响应理论中,自旋磁化率可以表示为推迟格林函数.对它所遵守的运动方程做哈特利-福克近似(HFA)和无规位相近似(RPA),再通过数值求解可得自旋磁化率.结果表明:没有R-SOC的静态磁化率Reχ(q,ω=0)随着库伦排斥势U的增大而增大,随温度T的增大而减小,库伦排斥势和温度对动态磁化率Reχ(q,ω=0)也有相似的影响.在加入R-SOC后,自旋轨道耦合的自旋磁化率实部在q=0附近形成了平底,而且平底宽度随VSO的增加而增大.同时自旋磁化率的虚部在平底边沿上呈现剧烈起伏.该效应可作为材料的自旋轨道耦合的显著标志.The effect of the Rashba spin-orbital coupling on the spin susceptibility of an electronic system strongly correlated with a two-dimensional square lattice is studied.According to the linear response theory,spin susceptibility can be expressed with a retarded Green function.The equations of the spin susceptibility can be numerically solved with a random phase approximation and a Hartree-Fock approximation.The numerical results show that in the absence of spin-orbital coupling the static spin susceptibility Reχ(q;ω=0)increases with the increase of the Coulomb interaction U and decreases with increasing temperature.The Coulomb interaction U and temperature T have similar effects on the dynamic susceptibility Reχ(q;ω=0).When the spin orbital coupling is added into the system,the real part of the spin susceptibilityχ(q)shows a flat base around the q=0.The size of the flat base increases significantly with increasing VSO while the imaginary part ofχ(q)shows a drastic fluctuation at the boundary of the flat base.Thus,this effect becomes a clear signature of the spin-orbital coupling of a system.

关 键 词：强关联系统 自旋轨道耦合 自旋磁化率 格林函数 RPA 

分 类 号：O469[理学—凝聚态物理]