Electron-phonon interaction and electron correlation in high temperature superconductors

Roles of electron-phonon interaction in the strongly correlated cuprates have been investigated theoretically. We have found that the oxygen displacement contributes to the d-wave paring in the region along the (0, 0)-(q(x), 0) and (0, 0)-(0, q(y)), where the strong coupling to the electrons is observed experimentally. Being based on the slave-boson picture applied to the t-J model and the Eliashberg theory, roles of electron-phonon interaction in the angle-resolved photoemission spectra (ARPES), tunneling spectra and optical conductivity are investigated. The vertex correction is essential to describe the electron-phonon interaction in the strongly correlated cuprates. (C) 2004 Elsevier B.V. All rights reserved.