Abstract :
The superconducting state, that gets induced in the GeH4 compound under the pressure at 20 GPa, is characterized by the high critical temperature T C ( μ ⋆ ) ∈ 〈 54.5 , 31.2 〉 K, where μ ⋆ is the Coulomb pseudopotential, and μ ⋆ ∈ 〈 0.1 , 0.3 〉 . Other thermodynamic parameters for the considered range of the Coulomb pseudopotential significantly differ from the predictions of the BCS model. In particular: (i) the ratio of the energy gap to the critical temperature ( R Δ ≡ 2 Δ ( 0 ) / k B T C ) changes from 4.07 to 3.88; (ii) the value of the parameter R C ≡ Δ C ( T C ) / C N ( T C ) decreases from 1.85 to 1.69, where Δ C denotes the specific heat jump, and CN is the specific heat of the normal state; (iii) the ratio R H ≡ T C C N ( T C ) / H C 2 ( 0 ) increases from 0.147 to 0.155; HC represents the thermodynamic critical field.
