The dispersion curves of the surface phonons of the TiC(100) surface have been determined over the entire Brillouin zone along the Γ-M direction by using electron energy loss spectroscopy. We have observed an acoustical branch (Rayleigh mode) and three optical branches (Lucas and Wallis modes and a new mode), which are assigned from a simple calculation based on the nearest-neighbour force constant model. The stiffening of the stretching force constant between the topmost layer and the second layer results in a new mode, which explains qualitatively the new observed optical mode.
ASJC Scopus subject areas
- Physical and Theoretical Chemistry
- Condensed Matter Physics
- Surfaces and Interfaces