The superconducting state in the B2H6 compound at 360 GPa

TL;DR

This study investigates the thermodynamic properties of superconducting B2H6 at 360 GPa, revealing high critical temperatures and deviations from BCS theory predictions across various Coulomb pseudopotential values.

Contribution

It provides detailed calculations of thermodynamic parameters of B2H6 superconductivity at high pressure using Eliashberg formalism, highlighting significant deviations from BCS theory.

Findings

Critical temperature ranges from 147 K to 87 K depending on Coulomb pseudopotential.

Energy gap to critical temperature ratio exceeds BCS predictions.

Specific heat jump ratio also exceeds BCS values.

Abstract

In the paper, the thermodynamic properties of the superconducting state in the $\rm{B_{2}H_{6}}$ compound have been characterized. The pressure of 360 GPa has been taken into account. The calculations have been carried out in the framework of the Eliashberg formalism for the wide range of the Coulomb pseudopotential: $\mu^{\star}\in<0.1,0.3>$. It has been found that the critical temperature ($T_{C}$) varies in the range from 147 K to 87 K, depending on the assumed value of the Coulomb pseudopotential. The ratio of the energy gap to the critical temperature ($R_{\Delta}\equiv 2\Delta(0)/k_{B}T_{C}$) significantly exceeds the value predicted by the BCS theory: $R_{\Delta}\in<4.24,3.98>$. In the similar manner behaves the ratio of the specific heat jump to the heat of the normal state ($R_{C}\equiv\Delta C(T_{C})/C^{N}(T_{C})$), namely: $R_{C}\in<2.33,2.17>$. The parameter $R_{H}\equiv T_{C}C^{N}(T_{C})/H^{2}_{C}(0)$, where $H_{C}(0)$ is the thermodynamic critical field, ranges from 0.144 to 0.168.