Walter A. Harrison

Resistivity due to dislocations in copper

Abstract The scattering of electrons by a dislocation with a hollow core is treated. It is found that the effect of such a core upon the electrical resistivity may be many times greater than the effect of the strain field. If the change in volume of the crystal due to dislocations is set equal to the core volume (of the order of one atomic volume per interatomic distance of dislocation), a rough calculation indicates that the change in resistivity for 1 per cent change in volume is about one-half of that observed in annealing experiments on cold-worked copper. It is suggested that the general magnitude of the interaction between conduction electrons and the core may be correct, even if the specific hollow-core model is not valid. Hence it appears that a consideration of the scattering by the core provides order-of-magnitude agreement with experiment for the resistivity due to dislocations.

THEORY OF PHONON DISPERSION IN METALS

A method for calculating from first principles the interaction between ions in a metal, and therefore, the phonon dispersion curves, is described. Developments in the understanding of metals which lead upto this approach are indicated and the main approach outlined. A description is given of the picture of the interaction between ions in a metal which emerges, and explicit curves representing this interaction in aluminum are displayed. The implications of the theory with respect to phonon dispersion are discussed; in particular, a possible cause of observed irregularities in the dispersion curves is indicated.