Abstract
The momentum-dependent line shape of the out-of-phase oxygen vibration as measured in recent neutron-scattering measurements is investigated. Starting from a microscopic coupling of the phonon vibration to a local crystal field, the phonon line shift and broadening is calculated as a function of transferred momentum in the superconducting state of The absolute magnitude of the shift is obtained as a function of momentum and is found to be in excellent agreement with experiment. It is shown that the anisotropy of the density of states, superconducting energy gap, and the electron-phonon coupling are all crucial in order to explain these experiments.
- Received 13 March 1998
DOI:https://doi.org/10.1103/PhysRevB.59.14618
©1999 American Physical Society