Raman Scattering Study on Fully Oxygenated YBa2Cu3O7 Single Crystals: x−y Anisotropy in the Superconductivity-Induced Effects

M. F. Limonov; A. I. Rykov; S. Tajima; A. Yamanaka

doi:10.1103/PhysRevLett.80.825

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Raman Scattering Study on Fully Oxygenated YBa2Cu3O7 Single Crystals: x−y Anisotropy in the Superconductivity-Induced Effects

M. F. Limonov, A. I. Rykov, S. Tajima, A. Yamanaka

DOI 10.1103/PhysRevLett.80.825 · Physical Review Letters

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Abstract

The Raman scattering spectra of fully oxygenated twin-free YBa2Cu3O7 crystals have been investigated. In addition to the out-of-plane and the in-plane anisotropy in all Ag phonon lines in the normal state, pronounced superconductivity-induced x−y anisotropy has been discovered in the softening and broadening of the 340cm−1 line below Tc. This suggests a substantial contribution of the chain superconductivity with a pairing symmetry different from that for the plane, or indicates that the superconducting gap amplitudes are different in the kx and ky directions (Δx≠Δy), as expected in the case of d+s wave gap.

Source-reported materials — not catalogue approval

Formula	Reported Tc (K)	Pressure (GPa)	Type
YBa2Cu3O7 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	86	Pressure not reported	unknown
YBa2Cu3Oy Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	92.5	Pressure not reported	unknown
YBa2Cu4O8 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	—	Pressure not reported	unknown