The Effect of Alloying on the Fermi Surface of Copper. II. Electron-scattering and Neck Cross Sections with Dilute Heterovalent and Transition Metal Solutes
The Fermi surface neck size and the scattering cross sections for the neck and [Formula: see text] belly orbits have been measured in dilute alloys of Zn, Al, Ge, Si, Ni, Co, Fe, Mn, and Cr in Cu. Earlier observations of rigid-band behavior for the neck size in Cu(Zn) and Cu(Al), while essentially substantiated by the present measurements, are now believed to be fortuitous; Cu(Ge) and Cu(Si) do not agree with a rigid-band prediction. The changes (generally reductions) of neck size in the transition metal alloys do not appear to be related directly to changes of electron concentration. The scattering anisotropy is rather small in the heterovalent alloys, the scattering being somewhat greater on the necks, but is large and in the opposite sense in the transition metal alloys. The magnitude and anisotropy of scattering is interpreted in terms of phase shifts associated with the impurities and the wave functions over the Fermi surface. There is evidence for additional scattering anisotropy in alloys exhibiting the Kondo effect.