摘要翻译：
研究了在易轴场中具有单轴各向异性的正方形格子Heisenberg和XY反铁磁体。基于基态的考虑和Monte Carlo模拟，分析了双锥结构在反铁磁和自旋flop相过渡区中的作用。特别地，在XXZ反铁磁体中加入一个单离子各向异性，根据各向异性的符号，可以观察到一个中间的双锥相或一个将两相分离的一级直接跃迁。在各向异性XY模型的情况下，反铁磁、自旋flop和双向结构中的基态在临界场的简并似乎导致反铁磁和自旋flop相之间的一个狭窄的无序相，由双向涨落控制，就像在XXZ模型的情况一样。
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英文标题：
《Biconical structures in two-dimensional anisotropic Heisenberg
  antiferromagnets》
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作者：
M. Holtschneider, W. Selke
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最新提交年份：
2007
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分类信息：

一级分类：Physics        物理学
二级分类：Statistical Mechanics        统计力学
分类描述：Phase transitions, thermodynamics, field theory, non-equilibrium phenomena, renormalization group and scaling, integrable models, turbulence
相变，热力学，场论，非平衡现象，重整化群和标度，可积模型，湍流
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英文摘要：
  Square lattice Heisenberg and XY antiferromagnets with uniaxial anisotropy in a field along the easy axis are studied. Based on ground state considerations and Monte Carlo simulations, the role of biconical structures in the transition region between the antiferromagnetic and spin--flop phases is analyzed. In particular, adding a single--ion anisotropy to the XXZ antiferromagnet, one observes, depending on the sign of that anisotropy, either an intervening biconical phase or a direct transition of first order separating the two phases. In case of the anisotropic XY model, the degeneracy of the ground state, at a critical field, in antiferromagnetic, spin--flop, and bidirectional structures seems to result, as in the case of the XXZ model, in a narrow disordered phase between the antiferromagnetic and spin--flop phases, dominated by bidirectional fluctuations.
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PDF链接：
https://arxiv.org/pdf/710.1251