周期性Hubbard模型密度矩阵函数的研究  

Research of the density-matrix functionals of the periodic Hubbard model

作　　者：郑勇林[1] 赵庆勋[1] 

机构地区：[1]重庆长江师范学院物理系,重庆408003

出　　处：《原子与分子物理学报》2007年第5期957-960,共4页Journal of Atomic and Molecular Physics

基　　金：重庆市教委科学技术研究项目(KJ061305);重庆长江师范学院重点学科建设基金(2003148)

摘　　要：在晶格密度泛函理论(LDFT)的框架内研究了哈巴德(Hubbard)模型,当考虑晶格内位置的单粒子密度矩阵γij、自旋S时,这个模型的相互作用能w[γij,S]为密度矩阵γij、总自旋S的函数.且当所有最近邻的γij=γ12时,对环状系统的w[γij,S]可获得精确的数值计算结果;文中同时还讨论了w[γij,S]函数在弱电子关联(γ102)和强电子关联(γi∞j)以及在γ1∞2<γ12<γ012区域限制下的性质.以非关联能w0[γ0ij,S]为单位标度的w[γij,S]表明的赝普适行为与g12=(γ12-γ1∞2)/(γ012-γ1∞2)函数一样.另外,w[γij,S]函数对不同总自旋S有一定的依赖.The Hubbard model is investigated in the framework of lattice density functional theory （LDFT）. It is considered that the interaction energy functional ω[γij,S] of the Hubbard model is investigated as a function of the single-particle density matrix γij with respect to the lattice sites, and total spin S. Exact numerical results are obtained for ω[γij,S] on rings, where γij = γ12 for all nearest neighbors. The properties of ω[γij,S] are discussed in the limits of weak （γ^012） and strong （γ∞ij） electronic correlations, and in the crossover region γ∞12〈γ12〈γ^012. Scaling of ω[γij,S] in units of the uncorrelated energy ω0[γ^0ij,S] shows a pseudo-universal behavior as a function of gl2 =（γ12-γ∞12）/（γ^012-γ∞12）. In addition, The functional dependence of ω[γij,S] is analyzed for different S.

关 键 词：HUBBARD模型 哈巴德哈密顿量 自旋转动对称 密度泛涵理论 

分 类 号：O56[理学—原子与分子物理]