Quantitative analysis of nonadiabatic effects in dense H${}_3$S and PH${}_3$ superconductors

Abstract

The comparison study of high pressure superconducting state of recently synthesized H${}_3$S and PH${}_3$ compounds 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 $2\Delta (0)/T_C$ ratio. We found that, for a fixed value of critical temperature ($178$ K for H${}_3$S and $81$ K for PH${}_3$), the nonadiabatic corrections reduce the Coulomb pseudopotential for H${}_3$S from $0.204$ to $0.185$ and for PH${}_3$ from $0.088$ to $0.083$, however, the electron effective mass and ratio $2\Delta (0)/T_C$ remain unaffected. Independently of the assumed method of analysis, the thermodynamic parameters of superconducting H${}_3$S and PH${}_3$ strongly deviate from the prediction of BCS theory due to the strong-coupling and retardation effects.

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Cited by in corpus (5)

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• Materials under high pressure: A chemical perspective
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• Classifying superconductivity in ThH-ThD superhydrides/superdeuterides
• The electron-phonon coupling constant, the Fermi temperature and unconventional superconductivity in the carbonaceous sulfur hydride 190 K superconductor