Abstract
Reflectivity spectra of mixed crystals are measured at 8 K in the far-infared spectral region: 40-125 μm with special emphasis on the semimetal-semiconductor transition (). The dielectric function is analyzed as a sum of contributions: Electron interband transitions with the transitions for and for , calculated within the assumption of nonparabolic bands; phonon contribution given by a two-mode behavior for all calculated with a phenomenological model taking into account long-range interactions and plasmon contribution. The experimental results can be accounted in the frame of the adiabatic approximation for all concentrations.
- Received 28 April 1975
DOI:https://doi.org/10.1103/PhysRevB.13.3558
©1976 American Physical Society