Observation of a local structural change atTcforTl2Ba2CaCu2O8by pulsed neutron diffraction

著者: Brian H. Toby, T. Egami, J. D. Jorgensen, M.A. Subramanian - Physical Review Letters 1990 被引用: 227

Deviations in atomic positions from those of the average crystallographic structure of superconducting ${\mathrm{Tl}}_{2}$${\mathrm{ba}}_{2}$${\mathrm{CaCu}}_{2}$${\mathrm{O}}_{8}$ were studied by pair-distribution function (PDF) analysis of pulsed-neutron-scattering data. The PDF shows a clear change in the local structure at the onset of superconductivity. In addition to the previously observed local displacements of Tl and O within the Tl-O sheets, correlated displacements of O and Cu perpendicular to the Cu-O plane have been found. The arrangement of the O atoms appears to be different above and below ${\mathit{T}}_{\mathit{c}}$.