| Popis: |
It is shown that the procedure of averaging over positions of scatterers interacts synergetically with the application of the diagonal-projection-operator (..delta..,..delta..') decomposition to yield an exact expression for the ac and dc conductivity for an arbitrarily ordered array of fixed potentials. The formula is evaluated to lowest order in the scattering strength for arrays of scatterers with various degrees of order from uncorrelated to periodic; it is a function of density, frequency, and temperature. dc conductivity, for example, is a minimum for a perfectly random array, increasing to infinity for a periodic lattice at T = 0. Application to thermal-disorder resistivity in metals is mentioned. In appendices we discuss pervious attempts to solve this problem, simplify the quantum-mechanical Green-Kubo formula, and calculate the conductivity of classical electrons moving among dilute uncorrelated scatterers. |
