The two-group model for noble metals: low-field Hall effect and DMR in the limit of high dislocation densities

Abstract

Low-field Hall effect (LFHE) data obtained at 4.2 K, and data on the deviations from Matthiessen's rule (DMR) obtained between 4.2-140K, of dislocated high-purity silver, gold and copper are compared in order to complete and extend a previous investigation of copper. The corrections to the two-group model (TGM) necessary to bring the anisotropy parameters for electron-dislocation scattering obtained from LFHE and DMR into coincidence are discussed in terms of the different Fermi surfaces and Fermi velocities as well as relaxation-time distributions. New insight is gained into the fact that these corrections are moderate, although the assumptions of the TGM are rather far from being fulfilled. The systematic changes of the anisotropy parameters estimated from the corrected TGM (0.09 for Ag, O.11 for Cu and 0.13 for Au) are in qualitative agreement with the Watts model of electron-dislocation scattering.