Theory of Impurity Resistance in Metals

A many-body technique is developed for the calculation of the dc resistivity of a Fermi fluid in the presence of a few, randomly scattered, fixed, impurities. A certain class of graphs yields an expression for the conductivity which is similar in form to the standard classical transport coefficient; but the decay time is determined by the scattering of single-particle-like excitations at the Fermi surface by screened impurities. A propagator method similar to that used in field theory is employed throughout the paper, and the perturbation-theoretic interpretation of this method is examined in some detail.