EFFECTS OF COULOMB INTERACTIONS BETWEEN FERMIONS ON SUPERCONDUCTIVITYIN BOSON-FERMION MODEL

Influence of Coulomb repulsion between fermions on stability of the su perconducting state in the model of boson-like local electron pairs hy bridized with wide-band fermions is studied. It is shown rigorously th at the Bose condensation of the local pairs implies a divergence of th e pairing susceptibility in the fermion subsystem. Charge carrier conc entration dependence of the critical temperature Te is evaluated with the help of random phase approximation and spectral properties of the bosons at T-c are analyzed.