摘要翻译:
在最近BaCuSi2O6实验的推动下,我们研究了层间受挫的层状二聚体磁体的磁激发和量子相变。我们考虑了两种情况:(A)一个晶格,每个晶胞有一个二聚体,并且有完美的层间挫败;(B)一个增大的晶胞,有不等价层,有和没有完美的挫败。在所有情况下,渐近低温下的临界行为都是三维的,但相应的交叉尺度可能很小。情况(B)中的磁有序可以用两个凝聚体来讨论;值得注意的是,完美的挫折使邻近效应无效。然后,顺序转换将被一般性地拆分,在可测量的属性中有明确的签名。利用广义键算符方法,计算了顺磁和反铁磁相的低温磁性能。根据BaCuSi2O6的现有实验数据,我们提出在这种材料中实现了层间不等价和非理想挫败的场景(B),很可能通过沿c轴的层间耦合的额外调制来实现。
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英文标题:
《Reduced dimensionality in layered quantum dimer magnets: Frustration vs.
inhomogeneous condensates》
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作者:
Oliver R\"osch, Matthias Vojta
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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:
Motivated by recent experiments on BaCuSi2O6, we investigate magnetic excitations and quantum phase transitions of layered dimer magnets with inter-layer frustration. We consider two scenarios, (A) a lattice with one dimer per unit cell and perfect inter-layer frustration, and (B) an enlarged unit cell with inequivalent layers, with and without perfect frustration. In all situations, the critical behavior at asymptotically low temperatures is three-dimensional, but the corresponding crossover scale may be tiny. Magnetic ordering in case (B) can be discussed in terms of two condensates; remarkably, perfect frustration renders the proximity effect ineffective. Then, the ordering transition will be generically split, with clear signatures in measurable properties. Using a generalized bond-operator method, we calculate the low-temperature magnetic properties in the paramagnetic and antiferromagnetic phases. Based on the available experimental data on BaCuSi2O6, we propose that scenario (B) with inequivalent layers and imperfect frustration is realized in this material, likely with an additional modulation of the inter-layer couling along the c axis.
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PDF链接:
https://arxiv.org/pdf/705.1351