We report results of inelastic neutron scattering measurements of phonon dispersions on a detwinned sample of YBaCu3O7 and compare them with model calculations. Plane oxygen bond stretching phonon branches disperse steeply downwards from the zone center in both the a and the b direction indicating a strong electron-phonon coupling. Half way to the zone boundary, the phonon peaks become ill-defined but we see no need to invoke unit cell doubling or charge stripe formation: lattice dynamical shell model calculations predict such behavior as a result of branch anticrossings. There were no observable superconductivity-related temperature effects on selected plane oxygen bond stretching modes measured on a twinned sample.
@article{arxiv.cond-mat/0209197,
title = {Oxygen Phonon Branches in Detwinned YBa2Cu3O7},
author = {D. Reznik and L. Pintschovius and W. Reichardt and Y. Endoh and H. Hiraka and J. M. Tranquada and S. Tajima and H. Uchiyama and T. Masui},
journal= {arXiv preprint arXiv:cond-mat/0209197},
year = {2007}
}
Comments
5 pages, 3 figures, To appear in Journal of Low Temperature Physics (Proceedings of MOS2002; Revised version (1) with many changes throughout the text