Acoustic phonon absorption by a 2D electron gas in the quatised Hall regime for odd filling factors

A new mechanism of sound phonon absorption by GaAs/AlGaAs heterostructure is considered for a 2D electron system which is spin dielectric. The phonons are absorbed by spin excitons, and two channels of absorption take place. The first one does not change the spin state of the system and leads to the absorption which vanishes as T→0. The second channel arising from electron spin-orbit coupling generates spin excitons which provide the finite rate of absorption at T=0.