Superconducting state in the atomic metallic hydrogen just above the pressure of the molecular dissociation

Abstract

Above the pressure of ∼500GPa, the molecular metallic hydrogen gets converted into the atomic phase. The properties of the superconducting state in the metallic hydrogen just above the molecular-atomic phase transition have been examined in the paper (p=539GPa). The numerical calculations have been conducted in the framework of the Eliashberg formalism. It has been stated that the critical temperature (TC) is equal to 360K when the Coulomb pseudopotential takes the value of 0.1. In the considered case, TC considerably exceeds the value calculated with the help of the McMillan or Allen–Dynes formula. The remaining thermodynamic parameters significantly diverge from the canonical values predicted by the BCS theory. In particular: RΔ≡2Δ(0)/kBTC=4.95, RC≡ΔC(TC)/CN(TC)=2.78, and RH≡TCCN(TC)/HC2(0)=0.126.