ELECTRON BOSON INTERACTION CAN HELP D-WAVE PAIRING - SELF-CONSISTENT APPROACH

We show that the critical temperature for the d wave pairing, which is due to the spin fluctuations in the 2D t-t' model, can be even increa sed in the presence of the strongly momentum (k) dependent electron-bo son (phonon, plasmon, exciton etc.) interaction. The condition for thi s effect is that, in comparison to the momentum-independent case, the electron-boson coupling must be increased at k approximate to 0 and de creased for large k. The possible mechanism for such a behavior of the coupling constant, based on strong correlations, is also discussed. T he problem is studied self-consistently in the framework of the strong -coupling Eliashberg equations, by taking into account spin and charge fluctuations as well as the electron-boson interaction.