Electron-impurity scattering in dilute alloys with lattice distortion. I. General theory

Abstract

Two expressions for the inverse relaxation time tau (nk)^-1 have been derived for the scattering of a Bloch electron by an impurity which may induce charge transfer and lattice distortion. The muffin-tin model was used. The first expression is based on the treatment of scattering by individual centres in the distorted system and is exact if the lattice distortion is not too large. In the derivation of the second expression the impurity with its distorted environment has been treated as a whole, so that cluster phase shifts are used. This expression is exact if the muffin-tin radius is small. If the muffin-tin radius is kept reasonable neither the first nor the second expression is exact for large lattice distortion. The theory is applicable to vacancy scattering as well.