The Superconducting State of the LiC6 Compound: The Effective Triangular Lattice Model

Abstract

Thermodynamic parameters of the superconducting state of the LiC₆ compound were calculated. Based on experimental data and results obtained using the density functional theory, the following input parameters for the effective triangular lattice model were adopted: hopping integral t = 355 meV, chemical potential µ = - 4.37 t, Coulomb pseudopotential µ* = 0.01, phonon energy ω₀=0.052 t, and electron–phonon interaction energy g₀ = 0.00931 t. Calculations allowed us to reproduce the experimental values of the electron–phonon coupling constant λ = 0.58 ± 0.05 and critical temperature T_C = 5.9 K. The dimensionless thermodynamic ratios were as follows: R_Δ = 3.73, R_C = 1.71, and R_H = 0.16. The obtained R_Δ , R_C , R_H values were compared with experimental data and density functional theory. It was shown that within the framework of the effective triangular lattice model, the thermodynamic properties of the superconducting phase of LiC₆ can be correctly reproduced. Additionally, the anisotropic structure of the electron–phonon coupling function and the anisotropic logarithmic phonon frequency function were discussed.