Coupled topological flat and wide bands: Quasiparticle formation and destruction

Flat bands amplify the effects from correlations. Lattices with destructive kinematic interference provide natural platforms 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. Here [1,2], we study a model with topological flat bands coupled with dispersive wide bands. Exponentially localized Wannier functions are constructed, which leads to a Kondo lattice description. We identify an orbital-selective Mott transition from the effective model and characterize the Kondo-driven quasiparticles and their destruction. We systematically address the conditions under which the orbital-selective Mott transition takes place. Our work provides a conceptual framework to address the strange-metal behavior in kagome metals and beyond.



[1] H. Hu, et al., arXiv: 2209.10396 (2022).



[2] L. Chen, et al., unpublished (2022).