Superconductivity-induced phonon softening in YBa2Cu3O7 observed by inelastic neutron scattering

N. Pyka; W. Reichardt; L. Pintschovius; G. Engel; J. Rossat-Mignod; J. Y. Henry

doi:10.1103/PhysRevLett.70.1457

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Superconductivity-induced phonon softening in YBa2Cu3O7 observed by inelastic neutron scattering

N. Pyka, W. Reichardt, L. Pintschovius, G. Engel, J. Rossat-Mignod, J. Y. Henry

DOI 10.1103/PhysRevLett.70.1457 · Physical Review Letters

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Abstract

Inelastic neutron scattering yielded the first information on superconductivity-induced frequency shifts for q≠0 phonons in YBa2Cu3Ox. For branches starting from the Raman-active mode at 340 cm−1 (10.2 THz), the shifts were found to decrease only slowly with increasing momentum transfer (x=7.0) or even exhibit a maximum at finite (x=6.92) when going along the [100] and [010] directions. They were independent of q in the [001] direction. The shifts were much smaller for the Au mode at 307 cm+1 and the Eu mode at 343 cm−1 and for q≠0 phonons related to these modes.

Source-reported materials — not catalogue approval

Formula	Reported Tc (K)	Pressure (GPa)	Type
YBa2Cu3O6.92 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	92	Pressure not reported	onset
YBa2Cu3O7.0 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	92	Pressure not reported	onset