Effects of coulomb interactions between fermions on superconductivity in boson-fermion model

摘要

Influence of Coulomb repulsion between fermions on stability of the su- perconducting state in the model of boson-like local electron pairs hybridized with wide-band fermions is studied. It is shown rigorously that the Base con- densation of the local pairs implies a divergence of the pairing susceptibility in the fermion subsystem. Charge carrier concentration dependence of the critical temperature. T_c is evaluated with the help of random phase approxi- mation and spectral properties of the bosons at T_c are analyzed.