Abstract
We have measured Raman spectra of several SiC polytypes ( , , ) made from natural silicon and . The isotope shifts of the phonon frequencies show characteristic variations with their effective wave vector in the zinc blende modification which arises from Brillouin zone backfolding. This allows us to determine the phonon eigenvectors of SiC for the dispersion branches along the [111] direction. The observed magnitudes of the Si and C ion displacements, as well as their relative phase, confirm bond charge model and ab initio calculations.
- Received 24 November 1998
DOI:https://doi.org/10.1103/PhysRevLett.82.3089
©1999 American Physical Society