On the critical temperature and the energy gap in dense SiH4(H2)2 at 250 GPa

TL;DR

This study calculates the critical temperature and energy gap of dense SiH4(H2)2 at 250 GPa, revealing their dependence on Coulomb pseudopotential and exceeding classical BCS ratios, with analytical formulas provided.

Contribution

It provides new calculations of $T_{C}$ and energy gap for SiH4(H2)2 at high pressure, including their dependence on Coulomb pseudopotential and analytical expressions.

Findings

$T_{C}$ decreases from 129.83 K to 81.40 K as $0.3$ increases.

Energy gap decreases from 50.96 meV to 30.12 meV with increasing $0.3$.

The ratio $R_{4}$ exceeds classical BCS predictions, ranging from 4.55 to 4.29.

Abstract

The critical temperature ($T_{C}$) and the energy gap ($2\Delta(T)$) for the superconductor SiH$_4$(H$_2$)$_2$ at 250 GPa have been calculated. The wide range of the Coulomb pseudopotential's values has been considered: $\mu^{\star}\in<0.1,0.3>$. It has been stated that $T_{C}$ decreases together with the increase of $\mu^{\star}$ from 129.83 K to 81.40 K. The low-temperature energy gap ($T\sim 0$ K) decreases together with the increase of the Coulomb pseudopotential from 50.96 meV to 30.12 meV. The high values of $2\Delta(0)$ mean that the dimensionless ratio $R_{\Delta}\equiv 2\Delta(0)/k_{B}T_{C}$ significantly exceeds the value predicted by the classical BCS theory. In the considered case: $R_{\Delta}\in<4.55,4.29>$. Due to the unusual dependence of the critical temperature and the energy gap on $\mu^{\star}$, the analytical expressions for $T_{C}(\mu^{\star})$ and $\Delta(\mu^{\star})$ have been given.