Quasiparticles for the quantum electron-impurity transport problem

Abstract

A quasiparticle formulation is developed to describe the transport properties of a gas of independent electrons which interact via a finite-range potential with a fixed random array of impurity ions. It is proved that the Kubo approach and the Kohn-Luttinger transport-equation approach yield identical results for the conductivity up to terms of order N 2 T 4, where N is the impurity density and T is the T matrix for scattering of quasiparticles from single impurities. It is shown that the quasiparticle velocity, and not the momentum matrix element of the current, appears in the final expression for the electrical conductivity.