Electronic Correlation in Cr-based kagome materials

The geometric frustration in certain line-graph based lattices leads to flat bands, among which the kagome lattice is a prototype. The flat dispersion amplifies the interaction effect, making these systems an ideal platform to study the interplay between band topology and electronic correlations. In particular, the flat bands, together with its nearby dispersive bands, could be effectively described by compact molecular orbitals with the associated Anderson lattice model, and Kondo-driven physics can emerge [1]. Recently, correlation phases have been observed in Cr-based kagome materials CsCr3Sb5 and CsCr6Sb6 [2-3]. With first principle methods and parton approaches, we study the local orbital representation of the flat bands, and the correlated electronic structure [4], which is also examined through ARPES experiment [5]. Broader implications of the strong correlated phases and topological flat bands will also be discussed.

[1] Lei Chen, et al, arXiv: 2307.09431; L. Chen et al, Nat. Comm.15, 5242 (2024); H. Hu et al Sci. Adv. 9, eadg0028 (2023).

[2] L. Yi, et al, Nature 632, 1032 (2024).

[3] B. Song, et al, arXiv: 2404.12374.

[4] F. Xie, et al, arXiv: 2403.03911.

[5] Y. C. Guo, et al, arXiv:2406.05293.