Impurity scattering in the high-temperature superconductors

Abstract

We investigate the impurity effects upon the superconducting state of the spin density wave (SDW) model based on the Hubbard model in a two-dimensional square lattice in the weak-coupling regime for both non-magnetic and magnetic impurities. We first study the ways in which the impurity scatterings influence the SDW order paremeter, from which we see that the SDW order is reduced by the impurity scatterings. We show that this destruction of the SDW order promotes the effective attractive interaction between the quasiholes. We derive, however, that the pair-breaking effect caused by the impurity scattering exceeds the increase of the attractive interaction, which indicates the destruction of the superconducting order by the both non-magnetic and magnetic impurity scatterings.