On the critical temperature and the energy gap in dense SiH4SiH4(H2H2)2 at 250 GPa

The critical temperature (TC) and the energy gap (2Δ(T)2Δ(T)) for the superconductor SiH4SiH4(H2H2)2 at 250 GPa have been calculated. The wide range of the Coulomb pseudopotential's values has been considered: μ⋆∈〈0.1,0.3〉μ⋆∈〈0.1,0.3〉. It has been stated that TC decreases together with the increase of μ⋆μ⋆ from 129.83 K to 81.40 K. The low-temperature energy gap (T∼0T∼0 K) decreases together with the increase of the Coulomb pseudopotential from 50.96 meV to 30.12 meV. The high values of 2Δ(0)2Δ(0) mean that the dimensionless ratio RΔ≡2Δ(0)/kBTCRΔ≡2Δ(0)/kBTC significantly exceeds the value predicted by the classical BCS theory. In the considered case: RΔ∈〈4.55,4.29〉RΔ∈〈4.55,4.29〉. Due to the unusual dependence of the critical temperature and the energy gap on μ⋆μ⋆, the analytical expressions for TC(μ⋆)TC(μ⋆) and Δ(μ⋆)Δ(μ⋆) have been given.

► Thermodynamic parameters of the superconducting state that induces in SiH4SiH4(H2H2)2 under the pressure at 250 GPa.
► The high critical temperature.
► The non BCS value of the ratio 2Δ/kBTC2Δ/kBTC.
► The large electron effective mass.