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

The critical temperature (TC) and the energy gap ( 2 Δ ( T ) ) for the superconductor SiH 4 ( H 2 )2 at 250 GPa have been calculated. The wide range of the Coulomb pseudopotentialʹs values has been considered: μ ⋆ ∈ 〈 0.1 , 0.3 〉 . It has been stated that TC decreases together with the increase of μ ⋆ from 129.83 K to 81.40 K. The low-temperature energy gap ( T ∼ 0 K) decreases together with the increase of the Coulomb pseudopotential from 50.96 meV to 30.12 meV. The high values of 2 Δ ( 0 ) mean that the dimensionless ratio R Δ ≡ 2 Δ ( 0 ) / k B T C significantly exceeds the value predicted by the classical BCS theory. In the considered case: R Δ ∈ 〈 4.55 , 4.29 〉 . Due to the unusual dependence of the critical temperature and the energy gap on μ ⋆ , the analytical expressions for T C ( μ ⋆ ) and Δ ( μ ⋆ ) have been given.