On the Boson-Fermion resonant model on a lattice

Authors:

• Roman Micnas

Abstract

We review briefly the properties of a mixture of mutually interacting bosons (bound electron pairs) and itinerant fermions on a lattice (the boson-fermion model). The calculations of the superconducting phase transition temperature (T_c) and the phase diagram are the main concern. The self-consistent T-matrix method is applied to determine the superconducting critical temperature from a pseudogap phase. The method takes into account the pairing fluctuations effects. The T-matrix results for T_c are given for a three-dimensional (3-D) cubic lattice with tight-binding dispersion of electrons and standard bosons, and they are also compared with those of the BCS- mean-field approximation. Our results describe the BCS-Bose-Einstein condensation crossover in the boson-fermion mixture with resonant interaction. The energy scales involved in the pseudogap formation are also analysed.