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  • Letter
  • Open Access

Electron correlations in the kagome flat band metal CsCr3Sb5

Fang Xie1,2, Yuan Fang1, Ying Li3, Yuefei Huang4, Lei Chen1, Chandan Setty1,5,6, Shouvik Sur1, Boris Yakobson4, Roser Valentí7 et al.

Qimiao Si1

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Phys. Rev. Research 7, L022061 – Published 10 June, 2025

DOI: https://doi.org/10.1103/PhysRevResearch.7.L022061

Abstract

Kagome metals offer a unique platform for investigating robust electron-correlation effects because of their lattice geometry, flat bands, and multiorbital nature. In the cases with active flat bands, recent theoretical studies have pointed to a rich phase diagram that contains not only electronic orders but also quantum criticality. Very recently, CsCr3Sb5 has emerged as a strong candidate for exploring such new physics. Here, using effective tight-binding models obtained from ab initio calculations, we study the effects of electronic correlations and symmetries on the electronic structure of CsCr3Sb5. The effective tight-binding model and Fermi surface comprise multiple Cr−d orbitals and Sb−p orbitals. The introduction of Hubbard-Kanamori interactions leads to orbital-selective band renormalization dominated by the dxz band, concurrently producing emergent flat bands very close to the Fermi level. Our analysis sets the stage for further investigations into the electronic properties of CsCr3Sb5, including electronic orders, quantum criticality, and unconventional superconductivity, which promise to shed much new light into the electronic materials with frustrated lattices and bring about new connections with the correlation physics of a variety of strongly correlated systems.

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Phys. Rev. Research 7, L022061– Published 10 June, 2025
  • Received 23 September 2024
  • Accepted 22 April 2025
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