The phonon properties of partially CuPtB-ordered Ga0.52In0.48P with degrees of ordering η=0,0.19,0.28,0.35,0.47 determined from generalized ellipsometry measurement of the near-band-gap order birefringence, are studied by far-infrared spectroscopic ellipsometry. We determine precise spectra of the anisotropic dielectric functions. With increasing η all Ga0.52In0.48P phonon modes split in E- and A1-type vibrations with polarization perpendicular and parallel to the sublattice ordering direction, respectively, and the mode frequencies shift continuously. We demonstrate here that the alloy-induced modes previously observed in highly disordered Ga0.52In0.48P [Phys. Rev. B 64, 155206 (2001)] have their origin in the ordered atomic arrangement of alike group-III atoms. We propose far-infrared dielectric anisotropy as a sensitive measure for sublattice ordering in multinary III-V alloys.
|Original language||English (US)|
|Number of pages||17568370|
|Journal||Physical Review B - Condensed Matter and Materials Physics|
|State||Published - Nov 15 2002|
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics