EMISSION OF BALLISTIC ACOUSTIC PHONONS BY QUANTUM EDGE STATES

Emission of ballistic acoustic phonons by quantum edge states of one s patial quantization subband has been studied in a two-dimensional elec tron gas formed at the GaAs/AlGaAs heteroface. The phonon emission due to the deformation and piezoelectric interactions are considered. An analytic expression for the emission intensity distribution in phonon momenta has been derived. Detailed analysis of the intensity distribut ion is made in low- and high-temperature regimes. Different positions of the Fermi level are considered. It is shown that at low temperature s the phonon emission is predominantly concentrated within a narrow co ne around the direction of the edge state propagation, while at high t emperatures it is around the magnetic field normal to the electron pla ne. The emission intensity decreases when the Fermi level falls. This diminution is exponential at low temperatures.