Two-dimensional electron-gas heating and phonon emission by hot ballistic electrons

We have used lateral injection of hot ballistic electrons to investigate heating of a two-dimensional electron gas. The electron temperature was found to oscillate with increasing injection energy, confirming optic phonon emission as the dominant inelastic process for electrons with excess energy above 36 meV. Our technique provides a method for determining the electron-electron scattering time of the hot electrons as a function of both energy and magnetic field. In the quantum Hall regime we found that hot-electron injection suppressed dissipationless transport, which we have interpreted as resulting from the excitation of cold edge-state electrons to higher Landau levels.