Abstract
We have performed micro-Raman-scattering experiments on ordered (Formula presented) alloy samples in three different geometries where the phonon wave vector is either parallel or perpendicular to the ordering axis of the crystal. By comparing results from the (1¯11) backscattering and right-angle scattering measurements with the (Formula presented) symmetry of the crystal, we found that the recently discovered peaks at 205 and 354 (Formula presented) in the Raman spectra of ordered alloys are due to longitudinal-phonon modes with (Formula presented) symmetry in these geometries. In the (110) backscattering geometry, selection-rule forbidden longitudinal-phonon modes appear in the Raman spectra measured in parallel polarizations. Possible mechanisms for this selection-rule violation are discussed.
Original language | American English |
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Pages (from-to) | 1888-1892 |
Number of pages | 5 |
Journal | Physical Review B - Condensed Matter and Materials Physics |
Volume | 56 |
Issue number | 4 |
DOIs | |
State | Published - 1997 |
NREL Publication Number
- NREL/JA-590-24431