Fig. 2: Decomposition of optical conductivity and intraband spectral weight analysis.

a–d Decomposed optical conductivity at several pressure points consisting of a Drude peak (green), a localization peak (blue), and multiple interband transitions (orange). The data at ambient pressure were taken from a previous study⁵². e, f Pressure evolution of the Drude and localization peaks, respectively. g Calculated spectral weight of the two intraband contributions (Drude and localization peaks). h Pressure dependence of the experimental plasma frequency deduced from the total intraband spectral weight as explained in the text and plasma frequency calculated by DFT. i Schematic pressure phase diagram of CsV₃Sb₅ as determined by several electrical transport, magnetic susceptibility, NMR, XRD, and μSR studies^{5,6,7,8,9,10,11,12,13,14,15,16,17}. The gray shaded areas mark critical pressure regions corresponding to (i) the vanishing of CDW state at ~2 GPa (ii) the disappearance of the first superconducting dome at around 9 GPa, and (iii) the re-emergence of superconductivity at approximately 12 GPa.