键算符平均场方法在一维1/2自旋体系中应用  

Investigation of one-dimensional spin-1/2 chains by bond-operator mean field method

作　　者：杜涛[1] 李鹏[1] 

机构地区：[1]四川大学物理科学与技术学院,成都610064

出　　处：《四川大学学报（自然科学版）》2011年第5期1107-1114,共8页Journal of Sichuan University(Natural Science Edition)

摘　　要：格点自旋体系是现在凝聚态理论研究的热点,对于这类强关联体系目前有很多近似处理方法,本文采用键算符平均场方法,研究了两个一维自旋体系.将体系哈密顿量用键算符表达,再用平均场近似处理该哈密顿量,通过对角化及求解平均场方程解出了平均场参量值,并讨论了基态和低能激发的性质.Spin model on lattice is the frontier 05 research in condensed matter physics. There are many methods to treat this strongly correlated system. In this work, we study two one-dimensional spin-1/2 Heisenberg chains using operator-bond mean field method. Spin operators can be represented by bond operators, then Hamiltons of these systems are compose of terms of bond operators. Using mean field method, we get a new Hamilton which can be diagonalized for each system and get mean field equations. Solving these equtions, values of mean field parameters and excitation energy spectrums are obtained and we discuss these results in this work.

关 键 词：键算符平均场 二聚体 平均场方程 波戈留波夫变换 

分 类 号：O481.3[理学—固体物理]