It is shown that in GaAs-AlAs superlattices the confined longitudinal-optic Raman phonons created via either deformation-potential or Fröhlich electron-phonon interaction are different. This effect is demonstrated by comparison of resonance and off-resonance Raman spectra. Phonons of A1 symmetry (point group D2d) dominate in resonance, while B2 phonons are stronger in the off-resonance case. The resonance profile of the A1 modes is discussed. We also report the observation of confined transverse-optic phonons under extremely resonant conditions.
ASJC Scopus subject areas
- General Physics and Astronomy