Naslov
Evidence for anharmonicity in axial Cu-O bonds in YBa_2Cu_3O_7 using XAFS

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

Vrsta, podvrsta i kategorija rada
Sažeci sa skupova, sažetak, znanstveni

Izvornik
Bulletin of Americal Physical Society / - : American Physical Society, 1990, 587-587

Skup
APS March meeting

Mjesto i datum
Anaheim (CA), Sjedinjene Američke Države, 12.03.1990. - 16.03.1990

Vrsta sudjelovanja
Predavanje

Vrsta recenzije
Nije recenziran

Ključne riječi
anharmonicity, XAFS

Sažetak
We present polarized XAFS measurements carried out in oriented samples of YBa_2Cu_3Q0_7 as a function of temperature in the region between 10 and 105K. The contribution from the Cu(1)-O(4) bond, isolated using usual Fourier transform techniques, indicates the presence of 2 different, Cu-O distances for temperatures T<~40K and T>~90K. Non linear least square fittings to single shell XAFS calculations using a backscattering amplitude and phase obtained from La_2CuO_4 and a radial distribution function derived from a \psi^4 potential V(u) = u^2 + u^4 but were performed. These fits support the evidence for 2 Cu-O distances that change with temperature, while the average Cu-O distance remains constant, and show that the Cu-O bond exhibits strong anharmonicity. Based on the implied couplings of this ionic motion to superconductivity, a scenario for high temperature superconductivity in which both phonon and electronic channels are synergistically involved is discussed.

Izvorni jezik
Engleski

Znanstvena područja
Fizika

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