Charge density waves in kagome metals are typically identified through long-range structural order, yet their fluctuating counterparts may play an equally important role in shaping electronic phases. Using ultrafast coherent phonon spectroscopy, the authors reveal that in hole-doped CsV₃Sb₅, strong charge density wave fluctuations persist far beyond the disappearance of static order, with picosecond correlation times. These fluctuations peak near a doping-tuned quantum phase transition that coincides with a minimum in the superconducting double dome. Their results establish fluctuating charge order as a robust and ubiquitous feature of kagome metals and highlight its potential influence on superconductivity and other emergent quantum phenomena.
Kongruengkit et al. (Thu,) studied this question.