Characterization of phonon-mediated superconductivity in lithium doping borocarbide

•Superconducting properties of lithium doping borocarbide.•High critical temperature.•Thermodynamic properties outside the scope of BCS theory.

The paper presents the superconducting properties determined for lithium doping borocarbide (Li2B3C). The Eliashberg theory is used to investigate the exact values of superconducting energy gap, critical temperature, electron effective mass, free energy and the remaining thermodynamic function which allowed us to determine dimensionless ratios, which significantly exceed the values arising from the Bardeen-Cooper-Schrieffer theory of superconductivity. In particular, the obtained results show that Li2B3C hold a promise as high-temperature superconductor with the critical temperature in the range from 76.72 K to 45.07 K for a wide range of Coulomb pseudopotential (μ⋆ ∈ 〈0.1,0.3〉). Other thermodynamic properties strongly depend on the depairing electron correlations, exception is the electron effective mass at the critical temperature, which takes value independent of assumed Coulomb pseudopotential.

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