From t-J to JT: Spin-charge-phonon-coupling in high temperature superconductors

Superconducting copper-oxides are modeled by a two-band Hubbard type model Hamiltonian which explicitly includes on-site and intersite electron-phonon interactions. The effects of both on the antiferromagnetic and superconduc ting state properties are investigated. In the antiferromagnetic regime the on-site electron-phonon interactions induce a squeezing of the band energi es and an isotope effect on the antiferromagnetic transition temperature T- N is predicted. In the superconducting phase the intersite electron-phonon couplings gain importance and induce a large increase in T-c especially if the difference in band energies is large.