Laflorencie Nicolas, Mila Frédéric
Laboratoire de Physique des Solides, Université Paris-Sud, UMR-8502 CNRS, 91405 Orsay, France.
Phys Rev Lett. 2009 Feb 13;102(6):060602. doi: 10.1103/PhysRevLett.102.060602.
Building on recent neutron and NMR experiments, we investigate the field-induced exotic criticality observed in the frustrated compound BaCuSi2O6 using a frustrated model with two types of bilayers. A semiclassical treatment of the effective hard-core boson model shows that perfect interlayer frustration leads to a 2D-like critical exponent varphi=1 without logarithmic corrections and to a 3D low temperature phase with different but nonvanishing triplet populations in both types of bilayers. These further suggest a simple phenomenology in terms of a field-dependent transverse coupling in the context of which we reproduce the entire field-temperature phase diagram with quantum Monte Carlo simulations.
基于最近的中子和核磁共振实验，我们使用具有两种双层结构的受挫模型，研究了在受挫化合物BaCuSi₂O₆中观察到的场致奇异临界性。对有效硬核玻色子模型的半经典处理表明，完美的层间受挫导致二维类临界指数φ = 1，且无对数修正，并导致三维低温相，两种双层结构中的三重态占据数不同但不为零。这些进一步表明了一种基于场依赖横向耦合的简单唯象学，在此框架下，我们用量子蒙特卡罗模拟重现了整个场-温度相图。
