Electron-electron and electron-phonon collision cross sections in CsV3Sb5

Abstract

AV3Sb5 (A=K, Rb, Cs) are kagome metals and superconductors, attracting much recent attention as nexus of multiple quantum states. Here, through a systematic study of electric and thermal transport of CsV3Sb5, we identify iy as a metallic Fermi liquid with moderate electronic correlations ans strong electron-phonon (e-ph) collision cross section. We observe contributions to the inelastic electrical resistivity, each dominating within a distinct temperature window. The prefactor of the T2 is consistent with the Kadowaki-Woods scaling for a Fermi liquid with moderate correlation. By performing thermal conductivity measurements at zero and finite magnetic field, we separate the electronic and the lattice contributions to the thermal conductivity. The Wiedemann-Franz law is is satisfied in the zero-temperature limit, while a downward deviation emerges at finite temperature due to the mismatch between the prefactors of the electrical and thermal quadratic resistivities, as reported in other metals. The Bloch-Grüneisen description of electron-phonon scattering successfully accounts for both electronic thermal and electrical transport, indicating a remarkably large e-ph collision cross section in CsV3Sb5.

Figures (9)

• Figure 1: Low Temperatures electrical resistivity of CsV$_3$Sb$_5$. (a) Resistivity from 2 K to 35 K for several applied magnetic fields along crystal c-axis. (b) Resistivity at zero magnetic field versus temperature square. The red line shows T-square resistivity for temperatures between 4 K and 10 K. (c) Residual resistivity at zero magnetic field versus temperature to the power 5. The red lines show estimated minimum and maximum T$^5$ resistivity. The gray area shows the incertitude on the T$^5$ resistivity.
• Figure 2: Thermal conductivity of CsV$_3$Sb$_5$ crystal. (a) Thermal conductivity from 2 K to 30 K for several applied magnetic fields along crystal c-axis. (b) Thermal conductivity divided by temperature, from 2 K to 30 K. Resistivity and thermal conductivity have been measured on the same sample.
• Figure 3: Separation between electrons and phonon contribution in thermal conductivity. (a) Difference in electronic and thermal conductivity between measurements under 0 T and 1 T. (b) L divided by L$_0$ obtained from measurements at 0 T and 1 T. (c) Phononic and electronic thermal conductivity under zero magnetic field. (d) The phonon mean free path, l$_{ph}$vs. temperature, in a log-log scale. It has been calculated using the kinetic formula $\kappa=\frac{1}{3}C v_s l_{ph}$, the reported sound velocity ($v_s=$1960 m.s$^{-1}$pang2023glasslike) and the experimentally measured heat capacity yang2023charge.
• Figure 4: Electrical thermal conductivity ($WT$). (a) WT at 0 T. (a) WT and $\rho$ versus temperature square. Red lines show T-square resistivity, for temperatures up to 7 K for $WT$ and 10 K for $\rho$. (b) WT without the constant and the quadratic term as function of temperature cube. The red lines show estimated maximum and minimum T-cube dependence for temperatures. The gray area shows the incertitude on the T-cube resistivity.
• Figure 5: a) Amplitude of the prefactor of T$^5$ resistivity in CsV$_3$Sb$_5$ and in several elemental metals as a function of Debye temperature. Dashed lines indicate correlation between metals belonging to the same column of the periodic table. b) Same for the prefactor of thermal resistivity (expressed in its original units of cm.K$^{-1}$. W$^{-1}$ and without multiplication by $L_0$.) The main source of listed values for elements are two tables in ref.Klemens1956. The amplitude of $B_3$ in gold is misprinted and the correct value is recovered by referring to data reported in ref. White_1953. We used ref. Desai1984RYAN1980158 for $A_5$ values of column 12 elements. Dotted lines are guides for eye connecting metals belonging to the same group. The figure indicates that, considering its Debye temperature, CsV$_3$Sb$_5$ has relatively large e-ph prefactors.