Abstract
Recent first-principles calculations of the phonon dispersion curves in have suggested the presence of anomalies in some of the curves, particularly in the longitudinal acoustical (LA) branch in the to A direction. Similar behavior has been observed in numerous other superconductors with higher than those of standard electron-phonon BCS superconductors. Phenomenological calculations of the LA dispersion based on both an acoustical plasmon and a “resonant polarization” mechanism are given here to emphasize the importance of these similarities.
- Received 2 April 2002
DOI:https://doi.org/10.1103/PhysRevB.66.014513
©2002 American Physical Society