Localized optical vibrational modes in GaSb/AlSb superlattices

The vibrational spectrum of short-period GaSb/AlSb superlattices in the frequency range of GaSb optical phonons is investigated in detail. Localization of transverse GaSb optical phonons in GaSb/AlSb superlattices is observed experimentally for the first time. The dispersions of TO and LO phonons in GaSb are measured.