Influence of strong-coupling and retardation effects on superconducting state in YB6 compound

In the framework of strong-coupling formalism, we have calculated the thermodynamic parameters of superconducting state in the YB6 compound. The values of critical temperature (TC) are 9.5 K and 7.9 K for the Coulomb pseudopotential μ⋆ = 0.1 and 0.2, respectively. In the paper, we have determined the low temperature values of order parameter (Δ(0)), specific heat jump at the critical temperature (ΔC(TC)), and thermodynamic critical field (HC(0)). The dimensionless thermodynamic ratios: RΔ=2Δ0/kBTC, RC=ΔCTC/CNTC, and RH=TCCNTC/HC20 are equal to: RΔμ⋆∈{4.48,4.35}, RCμ⋆∈{2.62,2.55}, and RHμ⋆∈{0.146,0.157}. Due to the significant strong-coupling and retardation effects (kBTC∕ωln ∼ 0.1) those values highly deviate from the predictions of BCS theory.