@article{64829242bb7743c9b84cf46f797270e7,
title = "Equivalence of optimized conventional and proximity electron tunneling (PET) for niobium",
abstract = "A comparison is made of effective phonon spectra α2F(ω) obtained by a fully corrected proximity electron tunneling spectroscopy (PETS) on recrystallized foils of Nb with new results from {"}conventional{"} junctions of the form Ag-Al2O3-Nb. The latter show the largest strong coupling phonon structure ever observed for Nb and lead directly to an α2F(ω) in good agreement with PETS. This comparison suggests the equivalence of the two techniques if clean and highly ordered NS proximity structures are employed.",
author = "Khim, {Z. G.} and D. Burnell and Wolf, {E. L.}",
note = "Funding Information: THE IMPORTANCE of extending the McMiilan-Rowell electron-phonon tunneling spectroscopy \[1 \] to the wide variety of transition-metal-related superconductors has been emphasized in recent years \[2\]O. ne approach which avoids the problem posed by the generally poor quality of transition metal oxides as tunneling barriers, is to use proximity electron tunneling (PET)junctions of the form C-A1203-A1-S, where C is a convenient counterelectrode and S is the superconductor of interest. In the case of clean and highly ordered NS structures in which the N-metal thickness, dt¢, is small (dt¢ ~ 4), quasiparticles Andreev-reflected by the pair potential discontinuity As-As at the NS interface propagate to the N-oxide interface allowing the phonon spectrum of S to be determined \[3\]I. n addition to these As(E) con-tributlons to the tunneling density of states, contributions are also present in general from the pair potential AS(E), which is enhanced by the proximity of S. The quantitative application of this PETS technique to Nb, including corrections for the induced pair potential As(E) hasr ecentlbye end escribe\d[ 4-6\]. The relative complexity of the full PET analysis, however, makes desirable an independent confirmation, preferably on similarly recrystallized foil substrates, of the PETS results, particularly the a=F(c0) function obtained. To this end we have recently fabricated {"}conventional{"} tunnel junctions of the form Ag-AI=Os-Nb. (Such structures, minimizing the exposure of the cleaned * Operated for the U.S. Department of Energy by Iowa State Univentty under contract W-7405-Eng-82. This re~sarc~ wag supported by the Director for Energy Research, Office of Basic Energy Sciences, WPAS-KC-02-02-02.",
year = "1981",
month = jul,
doi = "10.1016/0038-1098(81)91069-3",
language = "English (US)",
volume = "39",
pages = "159--161",
journal = "Solid State Communications",
issn = "0038-1098",
publisher = "Elsevier Limited",
number = "1",
}