Fig. 1: Crystal structure, Fermi surface, and electron irradiation effects on the charge-density-wave and superconducting transition temperatures in CsV₃Sb₅.

a Crystal structure of CsV₃Sb₅. b V-Sb1 plane viewed from the c-axis direction. Whereas the V atoms form a two-dimensional kagome network, the Sb1 atoms are located at the hexagonal centers. c Schematic of the 2D Fermi surface of CsV₃Sb₅. The circular (red) and hexagonal (green) Fermi surfaces around the Γ point are composed of the Sb p-orbitals and V d-orbitals, respectively, while the two triangular Fermi surfaces (blue and green) around the K point are formed by the V d-orbitals. d Temperature dependence of resistivity ρ(T) in CsV₃Sb₅ single crystals with irradiated doses of 0 (pristine, red), 1.3 (orange), 3.3 (green), and 8.6 (blue) C/cm². The RRR values for each sample are listed. Arrows indicate the CDW transition temperatures determined from the temperature derivative of ρ(T) (see Fig. 4b, f, j). Note that the ρ(T) curves for the irradiated samples do not shift parallel to that of the pristine sample, which can be naturally understood by considering that CsV₃Sb₅ is a multiband system (see Supplementary Information Sec. III). e Low-temperature resistivity below 6 K on a logarithmic scale. Arrows indicate the residual resistivity ρ₀ for each irradiated sample. f Temperature dependence of normalized frequency shifts of the TDO for each sample. g Superconducting and CDW transition temperatures T_c (left axis) and T^* (right axis) as a function of irradiation dose. T_c is defined as the temperature at which the resistivity becomes zero (filled red circles), and the superfluid density becomes finite (open red circles). T^* is defined as the temperature at which the derivative dρ/dT shows an abrupt change or dip (filled blue squares). h ρ₀ (left axis) and λ(0) (right axis) as a function of irradiation dose. For the estimation of λ(0), see Supplementary Information Sec. IV.