title: Quantitative analysis of nonadiabatic effects in dense H3S and PH3superconductors.
abstract: The comparison study of high pressure superconducting state of recently synthesized H3S and PH3compounds are conducted within the framework of the strong-coupling theory. By generalization of the standard Eliashberg equations to include the lowest-order vertex correction, we have investigated the influence of the nonadiabatic effects on the Coulomb pseudopotential, electron effective mass, energy gap function and on the 2Δ(0)/TCratio. We found that, for a fixed value of critical temperature (178 K for H3S and 81 K for PH3), the nonadiabatic corrections reduce the Coulomb pseudopotential for H3S from 0.204 to 0.185 and for PH3from 0.088 to 0.083, however, the electron effective mass and ratio 2Δ(0)/TCremain unaffected. Independently of the assumed method of analysis, the thermodynamic parameters of superconducting H3S and PH3strongly deviate from the prediction of BCS theory due to the strong-coupling and retardation effects.
authors.affiliation: Institute of Physics, Czestochowa University of Technology, Ave. Armii Krajowej 19, 42-200 Czestochowa, Poland.
authors.forename: Artur P
authors.initials: AP
authors.lastname: Durajski