Coherent manipulation of phonon emission rates in semiconductor heterostructures

Quantum interference between electron-lattice and electron-light interaction allows coherent control of optical phonon emission rates in semiconductors. We use a microscopic theoretical analysis to show that the longitudinal-optical-phonon-mediated return rate of electrons into the lowest electron subband of a GaAs/AlGaAs heterostructure can be controlled by the phase of a microwave field which resonantly couples two upper electronic subbands of the heterostructure. For the structure investigated we predict a variation of the relaxation rate by a factor of 2 between 400 and 900 fs. This effect may be interpreted as quantum interference between a single-phonon emission process and a single-phonon-two-photon process.