Electron-boson interaction can help d wave pairing. Self-consistent approach.

Lichtenstein A.I., Kulic M.L.

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 increased in the presence of the strongly momentum (k) dependent electron-boson (phonon, plasmon, exciton etc.) interaction. The condition for this effect is that, in comparison to the momentum-independent case, the electron-boson coupling must be increased at k approximately=0 and decreased for large k. The possible mechanism for such a behavior of the coupling constant, based on strong correlations, is also discussed. The 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.

Physica C, 245 186-92, 1995.

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