INTERLAYER TUNNELING IN A STRONGLY CORRELATED ELECTRON-PHONON SYSTEM

We discuss the role of interlayer tunneling for superconducting proper ties of strongly correlated (U-->infinity limit) two-layer Hubbard mod el coupled to phonons. Strong correlations are taken into account with in the mean-field approximation for auxiliary boson fields. To conside r phonon-mediated and interlayer tunneling contribution to superconduc tivity on equal footing we incorporate the tunneling term into the gen eralized Eliashberg equations. This leads to the modification of the p honon-induced pairing kernel and implies a pronounced enhancement of t he superconducting transition temperature in the d-wave channel for mo derate doping. In numerical calculations the two-dimensional band stru cture has been explicitly taken into account. The relevance of our res ults for high-temperature superconductors is briefly discussed.