Abstract
Tunneling studies of artificially prepared Nb-Cu superlattices have been performed. Individual layers were in the range 8-5000 with total sample thicknesses 1 m. The coupling strength 2kTc shows a continuous decrease from values of 3.8 (thick layers) appropriate for a strong-coupled superconductor toward the weak-coupled value of 3.5 (thin layers). Contrary to earlier theoretical predictions and reports of indirect experimental evidence, we find no evidence for electronic states within the superconducting energy gap. The energies of the Nb longitudinal and transverse acoustic (LA and TA) phonons are found to be unaltered from their bulk values down to layer thicknesses of 32. At 10 the TA peak remains unaltered in energy but significantly broadens while the LA peak becomes too broad to measure. These results, in conjunction with earlier Brillouin scattering measurements, imply large changes in the phonon dispersion as a function of layer thickness.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 3867-3870 |
| Number of pages | 4 |
| Journal | Physical Review B |
| Volume | 27 |
| Issue number | 6 |
| DOIs | |
| State | Published - 1983 |
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ASJC Scopus subject areas
- Condensed Matter Physics
Cite this
Tunneling studies of a metallic superlattice. / Yang, Q. S.; Falco, Charles M; Schuller, Ivan K.
In: Physical Review B, Vol. 27, No. 6, 1983, p. 3867-3870.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Tunneling studies of a metallic superlattice
AU - Yang, Q. S.
AU - Falco, Charles M
AU - Schuller, Ivan K.
PY - 1983
Y1 - 1983
N2 - Tunneling studies of artificially prepared Nb-Cu superlattices have been performed. Individual layers were in the range 8-5000 with total sample thicknesses 1 m. The coupling strength 2kTc shows a continuous decrease from values of 3.8 (thick layers) appropriate for a strong-coupled superconductor toward the weak-coupled value of 3.5 (thin layers). Contrary to earlier theoretical predictions and reports of indirect experimental evidence, we find no evidence for electronic states within the superconducting energy gap. The energies of the Nb longitudinal and transverse acoustic (LA and TA) phonons are found to be unaltered from their bulk values down to layer thicknesses of 32. At 10 the TA peak remains unaltered in energy but significantly broadens while the LA peak becomes too broad to measure. These results, in conjunction with earlier Brillouin scattering measurements, imply large changes in the phonon dispersion as a function of layer thickness.
AB - Tunneling studies of artificially prepared Nb-Cu superlattices have been performed. Individual layers were in the range 8-5000 with total sample thicknesses 1 m. The coupling strength 2kTc shows a continuous decrease from values of 3.8 (thick layers) appropriate for a strong-coupled superconductor toward the weak-coupled value of 3.5 (thin layers). Contrary to earlier theoretical predictions and reports of indirect experimental evidence, we find no evidence for electronic states within the superconducting energy gap. The energies of the Nb longitudinal and transverse acoustic (LA and TA) phonons are found to be unaltered from their bulk values down to layer thicknesses of 32. At 10 the TA peak remains unaltered in energy but significantly broadens while the LA peak becomes too broad to measure. These results, in conjunction with earlier Brillouin scattering measurements, imply large changes in the phonon dispersion as a function of layer thickness.
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U2 - 10.1103/PhysRevB.27.3867
DO - 10.1103/PhysRevB.27.3867
M3 - Article
AN - SCOPUS:0003767672
VL - 27
SP - 3867
EP - 3870
JO - Physical Review B-Condensed Matter
JF - Physical Review B-Condensed Matter
SN - 0163-1829
IS - 6
ER -