The Tomasch Effect in Epitaxial Lead Films Backed by Silver.

An elementary picture of the interacting superconductor quasiparticles is given followed by a synopsis of the several theories of the Tomasch effect and a discussion of its measurements. A procedure for the growth of epitaxial Pb films and the subsequent fabrication of tunnel junctions of these films is given. It is shown that a theory by T. Wolfram most nearly fits the experimental observations of the study. This theory is then used to indirectly obtain a value for the perturbation in the energy gap at the Pb-Ag interface. A technique is developed for unfolding multiple-oscillation Tomasch data and is used to obtain values for the Fermi velocity in Pb for several specific points on the Fermi surface.