Quantum oscillations in the cyclotron phonon emission from a heated two-dimensional electron gas

Oscillations have been observed in the phonon intensity IN emitted normal to a heated two-dimensional electron gas bridge in a Si metal-oxide-semiconductor field-effect transistor in a quantizing magnetic field as the sheet density is varied at constant power input. These oscillations ({~}0.3% of the total signal at 6 T and filling factor i=12) are attributed to changes in the angular distribution of the emission arising from variations in the small fraction of the total energy emitted from higher Landau levels caused by changes in the screening of the electron-phonon interaction with Fermi-level position.