On the Normal State of the High Temperature Superconductors

Based on a Fermi liquid model, we present several results on the normal state of the optimally doped and overdoped cuprate superconductors. Our main result is an analytic demonstration, backed by self-consistent numerical calculations, of the linear in temperature resistivity and linear in 1/(energy) optical conductivity, provided the interacting Fermi liquid has strong peaks in its density of states (van-Hove singularities in 2 dimensions) near the chemical potential. Moreover, we find that the interactions tend to pin these strong peaks close to the chemical potential. This fact compares favorably with experiment on a variety of cuprates. Finally, we show that the above scenario yields naturally the low energy dependence of the experimentally determined susceptibility, without reference to spin waves.