A quantitative proximity electron tunneling spectroscopy (PETS) is demonstrated for the study of strong coupling superconductors which do not form suitable insulating oxides for conventional McMillan-Rowell tunneling spectroscopy. Proximity junctions of the form C-Al2O3-Al/S are employed, with Al thickness dN ≤ 100 ». Here S is the superconductor of interest and C is any convenient counterelectrode. The physical basis for the method, experimental techniques, and data obtained from foils of Nb are presented. The results for Nb include the energy-dependent pair potential δS(E), the renormalization function Z(E), effective phonon spectrum α 2F(Ω), electron-phonon coupling constant λ, and Coulomb pseudopotential Μ*. A full discussion of the underlying theory and details of the methods of analysis employed to obtain, in addition, the pair potential of the Al proximity layer are contained in a following paper.
ASJC Scopus subject areas
- Atomic and Molecular Physics, and Optics
- Materials Science(all)
- Condensed Matter Physics