论文标题
完全沮丧的双层抗铁磁铁中竞争的单线地层的热临界点
Thermal critical points from competing singlet formations in fully frustrated bilayer antiferromagnets
论文作者
论文摘要
我们检查了完全沮丧的双层旋转1/2海森贝格模型中的地面相图和热相变。基于来自符号 - 问题的综合分析，无量子量蒙特卡洛模拟，扰动理论和自由能参数，我们确定了一阶量子相变点，该线路分别分离了两个竞争性的量子有序的地面状态，并分别在层间二聚体和plaquettes上具有显着的单线形状。在有限温度下，该线延伸至形成一阶热过渡的壁，该壁终止于热临界点线。从有效的ISIN模型描述方面的扰动方法，我们确定了对强化区域中临界温度量表的二次抑制。基于自由能的论点，我们进一步获得了低温二聚体 - 单林制度的完整相边界，这与量子蒙特卡洛数据非常吻合。
We examine the ground-state phase diagram and thermal phase transitions in a plaquettized fully frustrated bilayer spin-1/2 Heisenberg model. Based on a combined analysis from sign-problem free quantum Monte Carlo simulations, perturbation theory and free-energy arguments, we identify a first-order quantum phase transition line that separates two competing quantum-disordered ground states with dominant singlet formations on inter-layer dimers and plaquettes, respectively. At finite temperatures, this line extends to form a wall of first-order thermal transitions, which terminates in a line of thermal critical points. From a perturbative approach in terms of an effective Ising model description, we identify a quadratic suppression of the critical temperature scale in the strongly plaquettized region. Based on free-energy arguments we furthermore obtain the full phase boundary of the low-temperature dimer-singlet regime, which agrees well with the quantum Monte Carlo data.
