一维自旋轨道模型中自旋-轨道能隙产生机理分析

计算物理 ›› 2007, Vol. 24 ›› Issue (6): 693-697.

一维自旋轨道模型中自旋-轨道能隙产生机理分析

朱瑞

清华大学物理系, 北京 100084

收稿日期:2006-07-24 修回日期:2006-12-20 出版日期:2007-11-25 发布日期:2007-11-25
作者简介:朱瑞(1979-),Femaie,1iaoning Province,PhD,Rescarch in strong correlated systems especiaiiy in analysis of erotic quantum ground gtates and quantum phase transitions,Department of Physics,Tsinghua University,Beijing 100084.

Spin-orbital Energy Gap in One-dimensional Spin-orbital Model

ZHU Rui

Department of Physics, Tsinghua University, Beijing 100084, China

Received:2006-07-24 Revised:2006-12-20 Online:2007-11-25 Published:2007-11-25

摘要/Abstract

摘要： 讨论考虑洪特耦合的两带赫伯德模型得到的一维自旋轨道模型中自旋-轨道能隙的产生.运用SU(4)赝费米子表象下的平均场理论,计算求得价键序参数、准粒子激发谱能隙和自旋、轨道密度-密度关联函数随系统耦合参数变化的结果.随洪特耦合相互作用由零开始增强,系统激发谱能隙逐渐打开,并且系统在参数取值为J₁/J₂=1/3处由具有阻错的无序状态相变到自旋铁磁有序和轨道反铁磁有序的状态.

关键词: 自旋-轨道能隙, 洪特耦合, 平均场理论, SU(4)费米表象

Abstract: The spin-orbital energy gap in a one-dimensional spin-orbital model deduced from a degenerate Hubbard model with intrasite Hund rule coupling is studied.By using a mean-field method with SU(4) constraint fermion representation of spins and orbitals the valence bond order parameter,quasi-particle excitation gap and the spin and orbital density-density correlation functions are calculated.It is found that,as the Hund's coupling strength increases the excitation spectra show a gap and the magnetic configuration changes from a frustrating disordered state to a spin ferromagnetic and orbital antiferromagnetic ordered state at J₁/J₂=1/3.

Key words: spin-orbital energy gap, Hund rule coupling, mean-field theory, SU(4) constraint fermion representation

中图分类号:

朱瑞. 一维自旋轨道模型中自旋-轨道能隙产生机理分析[J]. 计算物理, 2007, 24(6): 693-697.

ZHU Rui. Spin-orbital Energy Gap in One-dimensional Spin-orbital Model[J]. CHINESE JOURNAL OF COMPUTATIONAL PHYSICS, 2007, 24(6): 693-697.

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