Hu Haoyu, Si Qimiao
Department of Physics and Astronomy, Rice Center for Quantum Materials, Rice University, Houston, TX 77005, USA.
Sci Adv. 2023 Jul 21;9(29):eadg0028. doi: 10.1126/sciadv.adg0028. Epub 2023 Jul 19.
Flat bands amplify correlation effects and are of extensive current interest. They provide a platform to explore both topology in correlated settings and correlation physics enriched by topology. Recent experiments in correlated kagome metals have found evidence for strange-metal behavior. A major theoretical challenge is to study the effect of local Coulomb repulsion when the band topology obstructs a real-space description. In a variant to the kagome lattice, we identify an orbital-selective Mott transition in any system of coupled topological flat and wide bands. This was made possible by the construction of exponentially localized and Kramers-doublet Wannier functions, which, in turn, leads to an effective Kondo-lattice description. Our findings show how quasiparticles are formed in such coupled topological flat-wide band systems and, equally important, how they are destroyed. Our work provides a conceptual framework for the understanding of the existing and emerging strange-metal properties in kagome metals and beyond.
平带增强了关联效应，目前受到广泛关注。它们为探索关联环境中的拓扑结构以及由拓扑结构丰富的关联物理提供了一个平台。最近在关联的 Kagome 金属中的实验发现了奇异金属行为的证据。一个主要的理论挑战是研究当能带拓扑结构阻碍实空间描述时，局域库仑排斥的影响。在 Kagome 晶格的一个变体中，我们在任何耦合拓扑平带和宽带的系统中识别出轨道选择性莫特转变。这是通过构建指数局域化和克莱默斯双重态的万尼尔函数实现的，反过来，这又导致了有效的近藤晶格描述。我们的发现展示了在这种耦合拓扑平带 - 宽带系统中准粒子是如何形成的，同样重要的是，它们是如何被破坏的。我们的工作为理解 Kagome 金属及其他材料中现有的和新出现的奇异金属特性提供了一个概念框架。
