Absence of an energy gap in measurements of Cu-O superconductors with high-resolution electron-energy-loss spectroscopy
R. B. Phelps, P. Akavoor, L. L. Kesmodel, A. L. Barr, J. T. Markert, J. Ma, R. J. Kelley, M. Onellion
DOI 10.1103/PhysRevB.50.6526 · Physical Review B
Active bibliographic source — not scientific approval
Bibliographic access preserves source history; it does not approve extracted materials or validate reported claims. Review warnings on each occurrence separately.
Abstract
We report extensive measurements of Bi2Sr2CaCu2O8 (Bi 2:2:1:2) and YBa2Cu3O7 (Y 1:2:3) single crystals with high-resolution electron-energy-loss spectroscopy (HREELS). Both as-grown and oxygen-annealed Bi 2:2:1:2 samples were studied. In all cases, peaks due to surface optical phonons were observed at loss energies from 24 to 80 meV. We see no evidence for the weak feature near 60 meV which has been previously reported and attributed to the superconducting energy gap. Our results demonstrate that the optical conductivity of high-temperature superconductors deduced from HREELS, like that deduced from infrared spectroscopy, does not exhibit the gaplike structure expected for a BCS superconductor.
Source-reported materials — not catalogue approval
| Formula | Reported Tc (K) | Pressure (GPa) | Type |
|---|---|---|---|
| Bi2Sr2CaCu2O8 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula. | 83 | Pressure not reported | onset |
| YBa2Cu3O7 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula. | 92 | Pressure not reported | onset |
Similar papers
Dependence of the energy gap on Tc: Absence of scaling in the copper oxide superconductors
similarity 0.97Yonghong Li et al.
Source status unknown — claims are unverified
Superconducting energy gap and normal-state reflectivity of single crystal Y-Ba-Cu-O
similarity 0.97Z. Schlesinger et al.
Source status unknown — claims are unverified
High-resolution angle-resolved photoemission spectroscopy of the momentum dependence of the superconducting gap in Bi2Sr2CaCu2O8
similarity 0.97T. Yokoya et al.
Source status unknown — claims are unverified
Strong Dependence of the Superconducting Gap on Oxygen Doping from Tunneling Measurements on Bi2Sr2CaCu2O8−δ
similarity 0.97N. Miyakawa et al.
Source status unknown — claims are unverified
Oxygen doping Bi2Sr2CaCu2O8+δ superconductors: Variations in the BiO-layer electronic states determined by scanning tunneling microscopy
similarity 0.96Zhe Zhang & Charles M. Lieber
Source status unknown — claims are unverified
Doping dependence of the O 1s core-level photoemission in Bi-Sr-Ca-Cu-O superconductors
similarity 0.96M. Qvarford et al.
Source status unknown — claims are unverified