Isotope effect and resistivity in the Hubbard model for d-wave superconductivity

For spin-fluctuation-induced d-wave superconductivity in a two-dimensional Hubbard model we calculate the suppression of T-c, the isotope exponent alpha, and the enhancement of the resistivity rho due to additional phonon interaction. The smallest T-c suppression and the largest alpha values are obtained for interactions alpha(2)F(q, omega) which are enhanced at q = 0. For a reasonably large coupling constant lambda(p) the enhancement of rho yields qualitative agreement with the data on YBa2Cu3O7. However, the largest values of alpha (similar to 0.2) lie at the lower limit of the measured values for reduced-T-c materials.