Thermal phase transitions in a honeycomb lattice gas with three-body interactions.
Thermal phase transitions in a honeycomb lattice gas with three-body interactions.
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具有三体相互作用的蜂窝晶格气体中的热相变
DOI：
10.1103/physreve.88.052135
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发表时间：
2013
期刊：
影响因子：
--
通讯作者：
S. Wessel
中科院分区：
文献类型：
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作者：
M. Lohöfer;L. Bonnes;S. Wessel
我们基于平行回火蒙特卡罗模拟，研究了蜂窝晶格上具有最近邻三体相互作用的经典（硬核）晶格气体模型中的热相变。该系统在 和 的分数填充下实现了不可压缩的低温相，这在之前的相关量子模型研究中已被确定。特别是，the 和 thephase 都表现出广泛的基态简并性，反映了蜂窝晶格上三体相互作用的受挫性质。发现该相的热熔化是一级不连续相变。另一方面，从热力学行为中，我们获得了异相四态 Potts 模型热转变的指示。我们发现，这种热波茨模型转变与相的低能流形内四个扩展扇区之一的选择有关，这是通过基态流形到嵌入式蜂窝超晶格上的硬核二聚体模型的精确映射获得的。
We study the thermal phase transitions in a classical (hard-core) lattice gas model with nearest-neighbor three-body interactions on the honeycomb lattice, based on parallel tempering Monte Carlo simulations. This system realizes incompressible low-temperature phases at fractional fillings of,andthat were identified in a previous study of a related quantum model. In particular, both theand thephase exhibit an extensive ground-state degeneracy reflecting the frustrated nature of the three-body interactions on the honeycomb lattice. The thermal melting of thephase is found to be a first-order, discontinuous phase transition. On the other hand, from the thermodynamic behavior we obtain indications for a four-states Potts-model thermal transition out of thephase. We find that this thermal Potts-model transition relates to the selection of one out of four extensive sectors within the low-energy manifold of thephase, which we obtain via an exact mapping of the ground-state manifold to a hard-core dimer model on an embedded honeycomb superlattice.