方-卡戈姆晶格上硬核玻色子不可压缩晶体的相图
Landscape of incompressible crystals of hard-core bosons on the square-kagome lattice
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中文总结 AI 辅助
该研究采用分层平均场理论，在方-卡戈姆晶格硬核玻色子模型中发现了密度为3/4的稳定不可压缩态，其对应自旋1/2 XXZ模型的半磁化平台，且预测了相关材料的额外磁化平台。
中文摘要 AI 辅助
我们采用超越常规原胞描述的分层平均场理论，研究方-卡戈姆晶格上的硬核玻色子模型。研究表明，基于最小原胞的方-卡戈姆晶格常规描述无法完全捕捉该晶格支持的不可压缩态层级，仅能捕捉密度为5/6和2/3的两个基于紧致局域态的相。在我们的方法中，我们重现了这些已确立的相，并通过扩大变分团簇发现了额外的不可压缩态，其中ρ=3/4相尤为稳定，通过Matsubara-Matsuda映射，其对应自旋1/2 XXZ模型的半磁化平台。我们还将该方法应用于两种实验相关的方-卡戈姆化合物，采用从第一性原理计算得到的交换参数，计算得到的磁化过程与现有实验结果吻合良好，并预测了这些材料中额外的平台结构。
英文摘要
We investigate a hard-core boson model on the square-kagome lattice using hierarchical mean-field theory beyond the conventional unit-cell description. We show that the conventional description of the square-kagome lattice based on its smallest unit cell does not fully capture the hierarchy of incompressible states supported by the lattice, but only captures the two compact-localized-state-based phases at densities $5/6$ and $2/3$. Within our approach, we reproduce these previously established phases and uncover additional incompressible states enabled by enlarging the variational cluster. Among these, the $ρ=3/4$ phase is found to be particularly robust, which, through the Matsubara-Matsuda mapping, corresponds to a half-magnetization plateau in the spin-$1/2$ XXZ model. We further apply our approach to two experimentally relevant square-kagome compounds using exchange parameters obtained from first-principles calculations. The calculated magnetization processes are in good agreement with available experimental results and predict additional plateau structures in these materials.
