Strong correlations and band topology in the kagome flat band material CsCr3Sb5

Flat band kagome materials present an ideal platform to study the cooperation between strong

correlations and band topology. A flat band develops from destructive interference, which

motivates the consideration of compact localized states and, more precisely, compact molecular

orbitals. This has led to a theoretical description of the correlations in coupled flat and dispersive

bands in terms of a Kondo lattice in the basis of the molecular orbitals; a phase diagram is found

featuring strong quantum fluctuations and metallic quantum criticality [1]. Such a phase diagram

has recently been realized in the chromium based kagome material CsCr3Sb5 which contains a

flat band near the Fermi energy [2], Here, using first principles, we examine the electronic

structure and band topology in this system. We study properties of Wannier orbitals formed from

the flat bands. Using these Wannier orbitals, we construct minimal interacting models and

address both the quantum fluctuations [1] and electronic orders [3].

[1] L. Chen et al., arXiv:2307.09431.

[2] Y. Liu et al., arXiv:2309.13514.

[3] C. Setty et al., arXiv:2105.15204.