Superconducting energy gap of YBa2Cu3O9−δ measured by far-infrared reflection
Hong-juan Ye, Wei Lu, Zhi-yi Yu, Xue-chu Shen, Bai-cai Miao, Yi-ming Cai, Yong-jia Qian
DOI 10.1103/PhysRevB.36.8802 · Physical Review B
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Abstract
The superconducting energy gap of the high-Tc superconductor YBa2Cu3O9−δ (Tc=90 K) has been measured by the far-infrared technique in the frequency range 30-150 cm−1 and the temperature range 4.2-200 K. The frequency-dependent reflectances of two different samples show a common feature near ωc≈125 cm−1 where the reflectance curves drop rapidly at very low temperature but are smooth at temperatures larger than 90 K. This indicates that the oxide superconductor YBa2Cu3O9−δ has a superconducting energy gap 2Δ0=15.5 meV at very low temperatures and that the ratio 2Δ0kBTc≈2.0 is close to that of superconductors La-Ba-Cu-O and La-Sr-Cu-O, but smaller than the Bardeen-Cooper-Schrieffer theoretical value of 3.5. The temperature dependence of the superconducting energy gap Δ(T) is also obtained.
Source-reported materials — not catalogue approval
| Formula | Reported Tc (K) | Pressure (GPa) | Type |
|---|---|---|---|
| YBa2Cu3O9-δ Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula. | 90 | Pressure not reported | unknown |
| YBa2Cu3O9-δ Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula. | 90 | Pressure not reported | unknown |
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