Bond operator theory of isotropic spin-1 antiferromagnetic chains

被引:36
作者
Wang, HT
Shen, JL
Su, ZB
机构
[1] CHINESE ACAD SCI,INST THEORET PHYS,BEIJING 100080,PEOPLES R CHINA
[2] CHINESE ACAD SCI,CTR CONDENSED MATTER PHYS,BEIJING 100080,PEOPLES R CHINA
来源
PHYSICAL REVIEW B | 1997年 / 56卷 / 22期
关键词
D O I
10.1103/PhysRevB.56.14435
中图分类号
T [工业技术];
学科分类号
08 ;
摘要
The bond operator representation of quantum S=1/2 spins with the singlet state being projected out is applied to investigate the isotropic spin-1 Heisenberg antiferromagnetic chain H=Sigma(i)[S-i.Si+1-beta(S-i.Si+1)(2)]. Tn the approximation of Bose condensation, the ground-state properties of the system and their beta dependences are studied. The results at Heisenberg point beta=0 and at valence-bond-solid (VBS) point beta=-1/3 agree quite well with the analytical, numerical, and experimental studies. The excitation spectrum is nonsymmetric with respect to k=pi/2 and shows a minimum at k=pi. The beta dependences of the ground-state energy and the excitation gap show the similarities between the Heisenberg point and VBS point. The related properties of the spin ladders are also discussed.
引用
收藏
页码:14435 / 14440
页数:6
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