MARGINAL FERMI-LIQUID BEHAVIOR WITHIN A FERMI-LIQUID THEORY

Abnormal properties of the normal state of high T-c superconductors ha ve lead to models which discard the normal Fermi liquid picture. We pr opose a phenomenological model to describe the electrons in a marginal Fermi liquid approach of a quasi-2D conductor exhibiting a Van Hove s ingularity at the Fermi level. We assume a self-energy with a Fermi li quid behaviour near the Fermi energy and a marginal behaviour for ener gies higher than a crossover energy omega(c). This leads to the destru ction of the Van Hove singularity and to the opening of a pseudogap ne ar the Fermi level. We show that the Pauli susceptibility is temperatu re dependent and we can relate the pseudogap width with the crossover energy omega(c).