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.