Direct Role of Structural Dynamics in Electron-Lattice Coupling of Superconducting Cuprates

• Published in: arXiv.org
• Main Authors: Carbone, F, D -S Yang, Giannini, E, Zewail, A H
• Format: Paper Journal Article
• Language: English
• Published: Ithaca Cornell University Library, arXiv.org 15.01.2009
• Subjects: Anisotropy; Copper; Coupling; Cuprates; Decay rate; Deformation mechanisms; Electron diffraction; Electron spin; Electrons; Femtosecond pulses; Heat exchange; High temperature superconductors; Physics - Strongly Correlated Electrons; Physics - Superconductivity; Spin exchange; Superconductivity; Superconductors
• ISSN: 2331-8422
• DOI: 10.48550/arxiv.0901.2355

The mechanism of electron pairing in high-temperature superconductors is still the subject of intense debate. Here, we provide direct evidence of the role of structural dynamics, with selective atomic motions (buckling of copper-oxygen planes), in the anisotropic electronlattice coupling. The transient structures were determined using time-resolved electron diffraction, following carrier excitation with polarized femtosecond heating pulses, and examined for different dopings and temperatures. The deformation amplitude reaches 0.5 % of the c-axis value of 30 A when the light polarization is in the direction of the copper-oxygen bond, but its decay slows down at 45 degrees. These findings suggest a selective dynamical lattice involvement with the anisotropic electron-phonon coupling being on a time scale (1 to 3.5 ps depending on direction) of the same order of magnitude as that of the spin exchange of electron pairing in the high-temperature superconducting phase.