Kagome materials offer a rich platform to explore the interplay of topology, geometrical frustration, and electronic correlations. Their band structures host Dirac crossings, flat bands, and van Hove singularities, making them highly sensitive to interaction-driven effects and symmetry breaking^1,2,3. The bilayer Kagome compounds CsV₆Sb₆ and CsCr₆Sb₆ crystallize in space group and contain a double Kagome layer formed by corner-sharing triangles stacked along the crystallographic c-axis^4,5,6. CsV₆Sb₆ is a weakly correlated metallic system with dispersive bands near the Fermi level⁵. In comparison, CsCr₆Sb₆ shows extremely flat bands dominated by Cr 3d states, strong electronic correlations, localized magnetic moments, and possibly heavy-fermion-like behavior^6,7. Compared to the well-studied AV₃Sb₅ (A = K, Cs, Rb) systems, these bilayer compounds remain largely unexplored mainly due to challenging crystal growth process. High-quality single crystals of CsV₆Sb₆ and CsCr₆Sb₆ were grown using a self-flux method. The synthesis is challenging due to the volatile and highly reactive nature of Cs, as well as the presence of multiple competing phases that are energetically close in stability. The crystals were characterized by energy dispersive X-ray spectroscopy, single-crystal X-ray diffraction and studied using Raman spectroscopy and transport measurements to probe their lattice dynamics and electronic behavior, respectively. In this contribution, we present details on the synthesis and physical properties of the selected compounds.

References

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[7] Zhang, R. et al. Nat Commun, 2425 (2026). https://doi.org/10.1038/s41467-026-70779-4

Acknowledgments: We acknowledge the funding by the Deutsche Forschungsgemeinschaft (DFG; German Research Foundation) Project-ID 422213477-TRR 288 (Project B03).