Quantum magnetism on the Cairo pentagonal lattice
Quantum magnetism on the Cairo pentagonal lattice
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DOI：
10.1103/physrevb.85.104415
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发表时间：
2012-01
影响因子：
3.7
通讯作者：
I. Rousochatzakis;A. M. Läuchli;R. Moessner
中科院分区：
文献类型：
--
作者：
I. Rousochatzakis;A. M. Läuchli;R. Moessner
我们对开罗五角晶格上的反铁磁海森堡模型进行了广泛的分析和数值研究，该模型是 Shastry-Sutherland 晶格的对偶，并在 $S=5/2$ 化合物 Bi${}_{2}$Fe${}_{4}$O${}_{9}$ 中得到了密切的实现。我们考虑一个由晶格对称性暗示的具有两个交换耦合的模型，并研究基态的性质作为它们的比率 $x$ 和自旋 $S$ 的函数。建立经典相图后，我们以渐进的方式切换量子力学，强调量子涨落在晶格两个不等价位点上的不同作用。 $S=1/2$ 最重要的发现包括 (i) 由于小 $x$ 处潜在的无序排序机制，共线相和四子晶格正交相之间存在令人惊讶的相互作用（与新兴的 ${J}_{1}$-${J}_{2}$ 有效模型相关） ${J}_{2}\ensuremath{\gg}{J}_{1}$)，以及 (ii) 在中间 $x$ 处具有 $d$ 波对称性的非磁性且可能的自旋向列相。
We present an extensive analytical and numerical study of the antiferromagnetic Heisenberg model on the Cairo pentagonal lattice, the dual of the Shastry-Sutherland lattice with a close realization in the $S=5/2$ compound Bi${}_{2}$Fe${}_{4}$O${}_{9}$. We consider a model with two exchange couplings suggested by the symmetry of the lattice, and we investigate the nature of the ground state as a function of their ratio $x$ and the spin $S$. After establishing the classical phase diagram, we switch on quantum mechanics in a gradual way that highlights the different role of quantum fluctuations on the two inequivalent sites of the lattice. The most important findings for $S=1/2$ include (i) a surprising interplay between a collinear and a four-sublattice orthogonal phase due to an underlying order-by-disorder mechanism at small $x$ (related to an emergent ${J}_{1}$-${J}_{2}$ effective model with ${J}_{2}\ensuremath{\gg}{J}_{1}$), and (ii) a nonmagnetic and possibly spin-nematic phase with $d$-wave symmetry at intermediate $x$.