论文标题
蜂窝二聚体磁铁和$ \ rm yb_2 \ rm si_2 \ rm O_7 $中的Bose-Einstein冷凝
Bose-Einstein condensation in honeycomb dimer magnets and $\rm Yb_2 \rm Si_2 \rm O_7$
论文作者
论文摘要
在量子二聚体磁铁$ \ rm yb_2si_2o_7 $的最新实验中观察到了一个不对称的玻色子凝结（BEC）圆顶，该实验是由“呼吸”蜂窝状Heisenberg模型建模的，该模型具有可能的偏头状态。我们报告了关键实验特征与磁模型数值模拟预测之间的显着一致性。可以准确捕获BEC DOME的临界场以及BEC DOME的临界温度，以及BEC阶段内两个机制的发生。此外，我们研究了各向异性在交换耦合和$ g $ tensor中的作用。虽然我们证实了先前的提议，即各向异性可以在小于完全极化场强的磁场处诱导零温度相变，但我们发现，在高于各向异性尺度的温度下，这种效应变得可忽略不计。取而代之的是，发现BEC DOME内部的两个方案是由于各向同性呼吸蜂窝Heisenberg抗fiferromagnet的非线性磁化行为所致。我们的分析是通过将密度基质重新归一化组（DMRG）方法与最小纠缠典型热状态（METTS）和量子蒙特卡洛（QMC）的有限温度技术相结合的。
An asymmetric Bose-Einstein condensation (BEC) dome was observed in a recent experiment on the quantum dimer magnet $\rm Yb_2Si_2O_7$, which is modeled by a "breathing" honeycomb lattice Heisenberg model with possible anisotropies. We report a remarkable agreement between key experimental features and predictions from numerical simulations of the magnetic model. Both critical fields, as well as critical temperatures of the BEC dome, can be accurately captured, as well as the occurrence of two regimes inside the BEC phase. Furthermore, we investigate the role of anisotropies in the exchange coupling and the $g$-tensor. While we confirm a previous proposal that anisotropy can induce a zero temperature phase transition at magnetic fields smaller than the fully polarizing field strength, we find that this effect becomes negligible at temperatures above the anisotropy scale. Instead, the two regimes inside the BEC dome are found to be due to a non-linear magnetization behavior of the isotropic breathing honeycomb Heisenberg antiferromagnet. Our analysis is performed by combining the density matrix renormalization group (DMRG) method with the finite-temperature techniques of minimally entangled typical thermal states (METTS) and quantum Monte Carlo (QMC).
