Unconventional superconductivity mediated solely by isotropic electron-phonon interaction

Abstract

Unconventional superconductivity is commonly linked to electronic pairing mechanisms, since it is believed that the conventional electron-phonon interaction (EPI) cannot cause sign-changing superconducting gap symmetries. Here, we show that this common understanding needs to be revised when one considers a more elaborate theory of electron-phonon superconductivity beyond standard approximations. We selfconsistently solve the full-bandwidth, anisotropic Eliashberg equations including vertex corrections beyond Migdal's approximation assuming the usual isotropic EPI for cuprate, Fe-based and heavy-fermion superconductors with nested Fermi surfaces. In case of the high-$T_c$ cuprates we find a $d$-wave order parameter, as well as a nematic state upon increased doping. For Fe-based superconductors, we obtain $s_{\pm }$ gap symmetry, while for heavy-fermion CeCoIn${}_5$ we find unconventional $d$-wave pairing. These results provide a proof-of-concept that EPI cannot be excluded as a mediator of unconventional and of high-$T_c$ superconductivity.

References in corpus (26)

• Topological insulators and superconductors
• Superconductivity in Iron Compounds
• A Common Thread: the pairing interaction for the unconventional superconductors
• Evidence for ubiquitous strong electron-phonon coupling in high-temperature superconductors
• Antiferromagnetic order and spin dynamics in iron-based superconductors
• Interfacial mode coupling as the origin of the enhancement of Tc in FeSe films on SrTiO3
• Nematic Fermi Fluids in Condensed Matter Physics
• An unusual isotope effect in a high-transition-temperature superconductor
• A Large Iron Isotope Effect in SmFeAsO1-xFx and Ba1-xKxFe2As2
• An Isotopic Fingerprint of Electron-Phonon Coupling in High-Tc Cuprates
• Ab initio lattice dynamics simulations and inelastic neutron scattering spectra for studying phonons in BaFe2As2: Effect of structural phase transition, structural relaxation and magnetic ordering
• Time of life as it is in LiFeAs
• Direct Evidence for a Magnetic f-electron Mediated Cooper Pairing Mechanism of Heavy Fermion Superconductivity in CeCoIn5
• Electron-Phonon Properties of Pnictide Superconductors
• Full-bandwidth Eliashberg theory of superconductivity beyond Migdal's approximation
• Multiband full-bandwidth anisotropic Eliashberg theory of interfacial electron-phonon coupling and high-T${}_c$ superconductivity in FeSe/SrTiO${}_3$
• Intrinsic and structural isotope effects in Fe-based superconductors
• Electron and phonon dispersions of the two dimensional Holstein model: Effects of vertex and non-local corrections
• d-wave superconductivity from electron-phonon interactions
• Small-q Phonon Mediated Unconventional Superconductivity in the Iron Pnictides
• What are the experimentally observable effects of vertex corrections in superconductors?
• Eliashberg theory for spin-fluctuations mediated superconductivity -- Application to bulk and monolayer FeSe
• Nematicity from mixed S_{+-} + d_{x^2-y^2} states in iron-based superconductors
• Multichannel superconductivity of monolayer FeSe on SrTiO${}_3$: Interplay of spin fluctuations and electron-phonon interaction
• Suppression of superconductivity by spin fluctuations in iron-based superconductors
• Unconventional superconductivity in the strong-coupling limit for the heavy fermion system CeCoIn${}_5$