Cascade of correlated electron states in the kagome superconductor CsV₃Sb₅

The kagome lattice of transition metal atoms provides an exciting platform to study electronic correlations in the presence of geometric frustration and nontrivial band topology^1–18, which continues to bear surprises. Here, using spectroscopic imaging scanning tunnelling microscopy, we discover a temperature-dependent cascade of different symmetry-broken electronic states in a new kagome superconductor, CsV₃Sb₅. We reveal, at a temperature far above the superconducting transition temperature T_c ~ 2.5 K, a tri-directional charge order with a 2a₀ period that breaks the translation symmetry of the lattice. As the system is cooled down towards T_c, we observe a prominent V-shaped spectral gap opening at the Fermi level and an additional breaking of the six-fold rotational symmetry, which persists through the superconducting transition. This rotational symmetry breaking is observed as the emergence of an additional 4a₀ unidirectional charge order and strongly anisotropic scattering in differential conductance maps. The latter can be directly attributed to the orbital-selective renormalization of the vanadium kagome bands. Our experiments reveal a complex landscape of electronic states that can coexist on a kagome lattice, and highlight intriguing parallels to high-T_c superconductors and twisted bilayer graphene.