CaLi2 superconductor under the pressure of 100 GPa: the thermodynamic critical field and the specific heat

Abstract

In the paper, the thermodynamic properties of the CaLi${}_2$ superconductor have been studied. It has been assumed the high value of the pressure: $p=100$ GPa. The thermodynamic critical field ($H_C$) and the specific heats for the superconducting and normal state ($C^S$ and $C^N$) have been obtained. The calculations have been made within the framework of the Eliashberg approach for the wide range of the Coulomb pseudopotential: ${\mu }^{\star }\in <0.1,0.3>$. It has been shown that the low-temperature critical field and the specific heat jump at $T_C$ strongly decrease if ${\mu }^{\star }$ increases. The value of the dimensionless ratio $R_C\equiv (C^S-C^N)/C^N$ at the critical temperature differs significantly from the value predicted by the BCS model. In particular, the parameter $R_C$ decreases from 1.83 to 1.73 with the increase of the Coulomb pseudopotential value. In the paper, the interpolation formulas for the functions $T_C({\mu }^{\star })$ and $R_C({\mu }^{\star })$ have been also given.

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