论文标题
在菱形石墨的平坦带中观察竞争，相关的基态
Observation of competing, correlated ground states in the flat band of rhombohedral graphite
论文作者
论文摘要
在晶体固体中，电荷和自旋的相互作用会导致各种新兴的量子接地态，尤其是在部分填充的拓扑平坦带中，例如Landau级别或“魔法”双层石墨烯。菱形石墨（RG）的探索少得多，这也许是最简单，结构上最完美的凝结物质系统，可容纳受对称性保护的平坦频带。通过扫描隧道显微镜，我们绘制了8、10和17层的扁平带电荷密度，并识别从Sublatice抗抗铁磁绝缘子与无间隙相关的Paramagnet之间竞争中出现的域结构。我们的密度 - 矩阵重新归一化组的计算解释了观察到的特征，并证明了相关性与迄今为止鉴定的基于石墨烯的磁性根本不同，形成了量子磁体的基态。我们的工作将RG确立为一个新平台，用于研究均值波动和纠缠占主导地位的均值相互作用以外的多体相互作用。
In crystalline solids the interactions of charge and spin can result in a variety of emergent quantum ground states, especially in partially filled, topological flat bands such as Landau levels or in 'magic-angle' bilayer graphene. Much less explored is rhombohedral graphite (RG), perhaps the simplest and structurally most perfect condensed matter system to host a flat band protected by symmetry. By scanning tunneling microscopy we map the flat band charge density of 8, 10 and 17 layers and identify a domain structure emerging from a competition between a sublattice antiferromagnetic insulator and a gapless correlated paramagnet. Our density-matrix renormalization group calculations explain the observed features and demonstrate that the correlations are fundamentally different from graphene based magnetism identified until now, forming the ground state of a quantum magnet. Our work establishes RG as a new platform to study many-body interactions beyond the mean-field approach, where quantum fluctuations and entanglement dominate.
