EXACT SPECTRA, SPIN SUSCEPTIBILITIES, AND ORDER-PARAMETER OF THE QUANTUM HEISENBERG-ANTIFERROMAGNET ON THE TRIANGULAR LATTICE

被引:342
|
作者
BERNU, B [1 ]
LECHEMINANT, P [1 ]
LHUILLIER, C [1 ]
PIERRE, L [1 ]
机构
[1] UNIV PARIS 10,F-92001 NANTERRE,FRANCE
来源
PHYSICAL REVIEW B | 1994年 / 50卷 / 14期
关键词
D O I
10.1103/PhysRevB.50.10048
中图分类号
T [工业技术];
学科分类号
08 ;
摘要
Exact spectra of periodic samples are computed up to N = 36, Evidence of an extensive set of low-lying levels, lower than the softest magnons, is exhibited. These low-lying quantum states are degenerated in the thermodynamic limit; their symmetries and dynamics as well as their finite-size scaling are strong arguments in favor of Neel order. It is shown that the Neel order parameter agrees with first-order spin-wave calculations. A simple explanation of the low-energy dynamics is given as well as the numerical determinations of the energies, order parameter, and spin susceptibilities of the studied samples. It is shown how suitable boundary conditions, which do not frustrate Neel order, allow the study of samples with N = 3p + 1 spins. A thorough study of these situations is done in parallel with the more conventional case N = 3p.
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页码:10048 / 10062
页数:15
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