ELECTRONIC-STRUCTURE OF DILUTE ALLOYS OF GALLIUM IN GOLD

Dilute alloys of Au(Ga), a system that exhibits only a small change in lattice constant on alloying, have been studied using the de Haas-van Alphen effect. The anisotropy of the Fermi surface changes are rather rigid band-like but the magnitude of the changes and the total volume change are significantly less than those corresponding to a valence difference of 2. Both the Fermi surface changes and the Dingle temperatures can be explained satisfactorily by the same phase shift parametrisation, which also gives a good value for the impurity resistivity. The Freidel phase shifts deduced from the parametrisation have the correct Friedel sum and are characterised by a relatively small s term and large d term. This indicates a conduction electron screening charge that is more spread out than a simple free electron treatment suggests.