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摘要翻译：
研究了在kagome网络上具有空间各向异性最近邻交换耦合的Heisenberg反铁磁体的性质，即在一个晶格方向上耦合J，在另两个方向上耦合J′。对于J/J′>1，该模型可以描述钒钛矿的磁性能。在经典极限下，它表现出两种基态：当J/J′<1/2时为亚铁磁态，当J/J′>1/2时为大的倾斜自旋态流形。为了自洽地包含量子效应，我们研究了原始SU(2)对称模型在大N极限下的Sp(N)对称推广。除了依赖于各向异性外，Sp(N)对称模型还依赖于测量量子效应重要性的参数kappa。我们的数值计算表明，在Kappa-J/J′平面上，系统呈现出一个丰富的相图，包括一个亚铁磁相、一个不公度相和一个解耦的链相，后两个链相具有短程和长程的有序性。我们证实了这些结果，表明不同相之间的边界和Sp(N)相图的其他几个特征可以通过解析计算来确定。最后，将一个块自旋微扰展开应用于原自旋1/2模型的三聚体形式，我们认为在强各向异性J/J′>>1的极限下，原模型的基态是一个共线有序的反铁磁体，它通过一个量子相变与非公度态分离。
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英文标题：
《Heisenberg antiferromagnet with anisotropic exchange on the Kagome
lattice: Description of the magnetic properties of volborthite》
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作者：
T. Yavors'kii, W. Apel, and H.-U. Everts
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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：Strongly Correlated Electrons 强关联电子
分类描述：Quantum magnetism, non-Fermi liquids, spin liquids, quantum criticality, charge density waves, metal-insulator transitions
量子磁学，非费米液体，自旋液体，量子临界性，电荷密度波，金属-绝缘体跃迁
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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：
We study the properties of the Heisenberg antiferromagnet with spatially anisotropic nearest-neighbour exchange couplings on the kagome net, i.e. with coupling J in one lattice direction and couplings J' along the other two directions. For J/J' > 1, this model is believed to describe the magnetic properties of the mineral volborthite. In the classical limit, it exhibits two kinds of ground states: a ferrimagnetic state for J/J' < 1/2 and a large manifold of canted spin states for J/J' > 1/2. To include quantum effects self-consistently, we investigate the Sp(N) symmetric generalisation of the original SU(2) symmetric model in the large-N limit. In addition to the dependence on the anisotropy, the Sp(N) symmetric model depends on a parameter kappa that measures the importance of quantum effects. Our numerical calculations reveal that in the kappa-J/J' plane, the system shows a rich phase diagram containing a ferrimagnetic phase, an incommensurate phase, and a decoupled chain phase, the latter two with short- and long-range order. We corroborate these results by showing that the boundaries between the various phases and several other features of the Sp(N) phase diagram can be determined by analytical calculations. Finally, the application of a block-spin perturbation expansion to the trimerised version of the original spin-1/2 model leads us to suggest that in the limit of strong anisotropy, J/J' >> 1, the ground state of the original model is a collinearly ordered antiferromagnet, which is separated from the incommensurate state by a quantum phase transition.
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PDF链接：
https://arxiv.org/pdf/704.1441
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