发表机构
Goethe-Universität（法兰克福歌德大学）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本研究通过动力学平均场理论分析Kagome-Hubbard模型，发现平带铁磁性及其导致的零温局域自旋涨落，揭示了平带简并的内在关联效应。
AI 中文摘要
Kagome金属展现出拓扑、电子关联和晶格动力学之间丰富的相互作用。近期在费米能级附近具有平带的Kagome材料的发现揭示了多种关联电子相。然而，阐明其微观起源仍具挑战性，因为现实描述需要同等考虑多轨道和竞争性相互作用。为了将关联效应与材料特定细节分离，并识别平带区域的基本物理，我们使用动力学平均场理论研究了平带填充下的单轨道Kagome-Hubbard模型。我们发现了平带铁磁性的强烈特征，与精确和平均场基态结果一致。此外，我们揭示了一种非常规的准有序相，其中部分填充的自旋极化平带钉扎在费米能级，导致局域自旋涨落持续到零温，这与传统铁磁体预期的经典行为形成鲜明对比。我们的结果表明，这些异常涨落是平带简并的内在结果，并为理解平带Kagome系统中的关联效应建立了最小框架。
英文摘要
Kagome metals exhibit a rich interplay of topology, electronic correlations, and lattice dynamics. Recent discoveries of Kagome materials with a flat band near the Fermi level have revealed a variety of correlated electronic phases. However, elucidating their microscopic origin remains challenging, as realistic descriptions require accounting for multiple orbitals and competing interactions on an equal footing. To disentangle correlation effects from material-specific details and identify the essential physics of the flat-band regime, we study the single-orbital Kagome-Hubbard model at flat-band fillings using dynamical mean-field theory. We find strong signatures of flat-band ferromagnetism, consistent with exact and mean-field ground-state results. Moreover, we uncover an unconventional quasi-ordered phase in which a partially filled spin-polarized flat band pinned at the Fermi level gives rise to persistent local spin fluctuations down to zero temperature, in striking contrast to the classical behavior expected for a conventional ferromagnet. Our results demonstrate that these anomalous fluctuations are an intrinsic consequence of the flat-band degeneracy and establish a minimal framework for understanding correlation effects in flat-band Kagome systems.
Comments7 pages, 3 figures
