title: Key pairing interaction in layered doped ionic insulators.
abstract: A controversial issue on whether the electron-phonon interaction (EPI) is crucial for high-temperature superconductivity or it is weak and inessential has remained one of the most challenging problems of contemporary condensed matter physics. We employ a continuum random phase approximation for the dielectric response function allowing for a self-consistent semianalytical evaluation of the EPI strength, electron-electron attractions, and the carrier mass renormalization in layered high-temperature superconductors. We show that the Fröhlich EPI with high-frequency optical phonons in doped ionic lattices is the key pairing interaction, which is beyond the BCS-Migdal-Eliashberg approximation in underdoped superconductors, and it remains a significant player in overdoped compounds.
authors.affiliation: Department of Physics, Loughborough University, Loughborough LE11 3TU, United Kingdom.
authors.forename: A S
authors.initials: AS
authors.lastname: Alexandrov
authors.forename: A M
authors.initials: AM
authors.lastname: Bratkovsky