Theoretical studies of the effect of pair scattering process on two-gap superconductivity in Eliashberg theory

摘要

Two-gap superconductivity is investigated from the viewpoint of strong electron-phonon coupling including effective electron-electron interaction within an extension of the Eliashberg theory. The two-band Eliashberg theory is extended to a more general formalism, including the pair scattering process between two bands. We present a coupled extended Eliashberg equation. We discuss the contribution of effective electron-electron interaction and the electron-phonon coupling to two-gap superconductivity in relation to frequency dependence, using the extended Eliashberg equation and a model for phonon spectral density. (c) 2006 Wiley Periodicals, Inc.