Thermodynamics of the superconducting state in Calcium at 200 GPa

TL;DR

This study investigates the thermodynamic properties of superconducting Calcium at 200 GPa, revealing deviations from BCS predictions and showing how Coulomb pseudopotential influences key thermodynamic ratios.

Contribution

The paper provides detailed calculations of thermodynamic parameters of Calcium's superconducting state at high pressure, including effects of Coulomb pseudopotential, with analytical and numerical analysis.

Findings

Specific heat jump decreases with Coulomb pseudopotential.

Thermodynamic ratios differ from BCS model predictions.

Numerical results are supported by analytical methods.

Abstract

The thermodynamic parameters of the superconducting state in Calcium under the pressure at 200 GPa were calculated. The Coulomb pseudopotential values ($\mu^{\star}$) from 0.1 to 0.3 were taken into consideration. It has been shown, that the specific heat's jump at the critical temperature and the thermodynamic critical field near zero Kelvin strongly decrease with $\mu^{\star}$. The dimensionless ratios $r_{1}\equiv \Delta C(T_{C})/C^{N}(T_{C})$ and $r_{2}\equiv T_{C}C^{N}(T_{C})/H^{2}_{C}(0)$ significantly differ from the predictions based on the BCS model. In particular, $r_{1}$ decreases from 2.64 to 1.97 with the Coulomb pseudopotential; whereas $r_{2}$ increases from 0.140 to 0.157. The numerical results have been supplemented by the analytical approach.