SPIN FLUCTUATION EFFECTS ON A QUASI-2D ITINERANT ELECTRON-SYSTEM - A MICROSCOPIC MODEL FOR THE MARGINAL FERMI-LIQUID

We study a model of itinerant two-dimensional electron system exhibiting Van Hove and nesting singularities of the Fermi surface at half-filling of the band. We consider the spin fluctuation electron-electron scattering as the dominant scattering mechanism. This yields a marginal Fermi liquid behaviour at half-filling and a crossover from a normal Fermi liquid to a marginal one away from half-filling. Density of states, magnetic susceptibility, spin excitation spectrum, resistivity, thermopower and the phase diagram using BCS theory obtained by this simple model are in a qualitative agreement with high T(c) superconductors.