Evidence for an axial oxygen-centered lattice fluctuation associated with the superconducting transition in YBa2Cu3O7

J. Mustre de Leon; S. D. Conradson; I. Batistić; A. R. Bishop

doi:10.1103/PhysRevLett.65.1675

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Evidence for an axial oxygen-centered lattice fluctuation associated with the superconducting transition in YBa2Cu3O7

J. Mustre de Leon, S. D. Conradson, I. Batistić, A. R. Bishop

DOI 10.1103/PhysRevLett.65.1675 · Physical Review Letters

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Abstract

The axial oxygen contributions to the Cu K-edge, polarized, extended x-ray-absorption fine structure of YBa2Cu3O7 are analyzed from 10≤T≤105 K, using a novel approach in which the radial distribution function is directly calculated from model potentials. The best fit is obtained with a double-well potential with two nearly equally populated O(4) sites 0.13 Å apart. The site separation decreases 0.02 Å in a region near Tc. This perturbation in the structure is accompanied by a large increase of the tunneling frequency of ∼80 K between the two wells, suggesting a coupling between superconducting fluctuations and nonlinear phonons.

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.	90	Pressure not reported	unknown