Excitonic absorption and superconductivity in YBa2Cu3O7−y
K. Kamarás, C. D. Porter, M. G. Doss, S. L. Herr, and D. B. Tanner, D. A. Bonn, J. E. Greedan, A. H. O’Reilly, C. V. Stager, T. Timusk
DOI 10.1103/PhysRevLett.59.919 · Physical Review Letters
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Abstract
Optical and neutron-diffraction studies of superconducting and nonsuperconducting samples of YBa2Cu3O7−y are described. Superconducting samples, with y≊0.1, showed two strong electronic transitions, at 3000 cm−1/0.37 eV and at 20 000 cm−1/2.5 eV, which are interpreted as charge-transfer bands (i.e., excitons). Nonsuperconducting samples, with y≊0.8 (prepared by heating of superconducting samples in vacuum to deplete the oxygen content), did not show these features. Our measurements support an excitonic mechanism for the superconductivity in high-Tc copper oxide compounds.
Source-reported materials — not catalogue approval
| Formula | Reported Tc (K) | Pressure (GPa) | Type |
|---|---|---|---|
| YBa2Cu3O7-y Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula. | 93 | Pressure not reported | unknown |
| YBa2Cu3O6.9 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula. | 93 | Pressure not reported | unknown |
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