LOCALIZATION OF ACOUSTICAL MODES DUE TO THE ELECTRON PHONON INTERACTION WITHIN A 2-DIMENSIONAL ELECTRON-GAS

We study the localization of acoustical modes within a two-dimensional electron gas (2DEG) due to only the electron-phonon interaction. The localized modes split out from the bulk phonons even at uniform lattice parameters, when the 2DEG is created by means of modulation doping, for example under delta-doping. The effect is more pronounced when the wave vector q of the modes increases and is maximum at q = 2k(F) (k(F) is the Fermi wave vector). In the case of several electron sheets the additional features of the localization effect appear.