Coulomb interaction in disordered metals and HTSC

Abstract We consider underdoped or overdoped cuprates as disordered conductors. The diffusion coefficient D can be as low as 10 −5 m 2 s −1 . Under these conditions Coulomb interaction between electrons must be taken into account. The main effect is to open a dip in the density of state near the Fermi level. We show that this model explains most of the observed features of the so-called “pseudogap” in the normal state including its value, anisotropy and variation with doping. Such a model applied to disordered metals explains the dips observed in conductance measurements.