Hot magneto-phonon and electro-phonon resonances in heterostructures

When the energy separation of two quantum levels equals the energy of an LO phonon, resonant interaction occurs which leads to an enhancement of the scattering rate and consequently to a suppression of the conductivity. This effect is called magneto-phonon resonance (MPR) when the resonant scattering occurs between two Landau levels, and electro-phonon resonance (EPR) when the scattering occurs between two electrical subbands. The authors discuss both effects in GaAs/Al_xGa_1-xAs heterostructures under hot-electron conditions. The influence of the heating of the electrons on the resonant condition and the amplitude of the effect is studied.