Frieze charge stripes in a correlated kagome superconductor
摘要
In kagome metals, geometric frustration, electronic correlations and band topology combine to produce a wide range of intriguing phenomena. Among them, CsCr3Sb5 offers an opportunity to investigate unconventional superconductivity in a strongly correlated kagome system, with indications of frustrated magnetism and quantum criticality. Here we demonstrate a cascade of density-wave transitions with distinct symmetries in bulk single crystals of CsCr3Sb5. Using spectroscopic imaging scanning tunnelling microscopy, we uncover a unidirectional density wave that breaks all mirror symmetries—resembling a chiral density wave—but that also retains a mirror glide symmetry. We refer to this as a frieze charge stripe order phase, as its symmetry properties correspond to one of the fundamental frieze symmetry groups. A combination of high-resolution imaging, Fourier analysis and theoretical simulations reveals the key role of sublattice degrees of freedom in stabilizing this phase, which is characterized by internal chiral textures of opposite handedness. These findings suggest that superconductivity in CsCr3Sb5 emerges from this distinct density wave state and provide fresh insights into realizing electronic phases governed by frieze symmetry groups in quantum materials.