The dispersion curves of both the optical and acoustical surface phonons in the superconducting compounds NbC(100) and TaC(100) have been determined over the entire Brillouin zone of the M symmetry axis by use of angle-resolved high-resolution electron-energy-loss spectroscopy. In contrast to the bulk phonon, no anomalies (dip) due to the electron-phonon coupling in the dispersion curves of the longitudinal phonon have been found at these surfaces. Conversely, the in-plane force constant between carbon and metal atoms is strongly enhanced there.
ASJC Scopus subject areas
- Physics and Astronomy(all)