A. Mlayah et al., RESONANT RAMAN-SCATTERING IN GAAS ALAS SUPERLATTICES - THE ROLE OF ELECTRON STATE MIXING/, Physical review. B, Condensed matter, 53(7), 1996, pp. 3960-3965
In this work, resonant Raman measurements on a short-period GaAs/AlAs
superlattice are presented. Under resonant excitation, near the direct
band gap, zone-edge acoustic phonons are observed. Similar scattering
has been also recorded in the resonant Raman spectra of AlxGa1-xAs al
loy layer. We show that intervalley electron scattering is at the orig
in of the observed similarities. This scattering is attributed to the
superlattice potential for the GaAs/AlAs superlattice, and to the pote
ntial fluctuations for the AlxGa1-xAs alloy. The present analysis give
s a clear interpretation of the Raman scattering by zone-edge acoustic
phonons in both systems. Moreover, the role of disorder is discussed
in terms of an activation of folded acoustic and coupled confined-inte
rface phonons.