Thermodynamic Properties of Spin 1/2 Antiferromagnetic Heisenberg Model on the Square Lattice
Thermodynamic Properties of Spin 1/2 Antiferromagnetic Heisenberg Model on the Square Lattice
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方晶格上自旋1/2反铁磁海森堡模型的热力学性质
DOI：
10.1143/jpsj.57.1934
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发表时间：
1988
影响因子：
1.7
通讯作者：
S. Miyashita
中科院分区：
文献类型：
--
作者：
S. Miyashita
用量子蒙特卡罗方法研究了自旋1/2反铁磁海森堡模型的热力学性质。序参量的涨落，即交错磁化的平方，在低温下表现出较大的增强。研究了基态阶参量的大小依赖关系，并将其拟合为与大小有关的幂律形式，即涨落发散时不存在长程阶参量。研究了交错磁化率，即交错磁化的正则（Kubo’s）相关，发现与交错磁化的平方相比，量子涨落在很大程度上抑制了交错磁化率。发现均匀场的磁化率有一个宽峰。
Thermodynamic properties of spin 1/2 antiferromagnetic Heisenberg model are investigated by a quantum Monte Carlo method. Fluctuation of the order parameter, namely the square of staggered magnetization, shows large enhancement at low temperatures. Size dependence of the order parameter in the ground state is investigated and it is fitted by a form with a power law dependence on the size which means that the long range order does not exist although the fluctuation diverges. Staggered susceptibility, namely the canonical (Kubo's) correlation of staggered magnetization, is also investigated and is found to be largely suppressed by quantum fluctuation compared with the square of staggered magnetization. Susceptibility for the uniform field is found to have a broad peak.