GIANT MAGNETOPHONON OSCILLATIONS OF THE TUNNELING RELAXATION RATE IN DOUBLE-QUANTUM WELLS

Electron tunneling relaxation, accompanied by spontaneous emission of optical phonons, is considered in a double quantum well subject to a p erpendicular magnetic field. When the energy splitting DELTA(T), betwe en the (lowest) levels in the left and right wells, is larger than the optical phonon energy, electrons can emit optical phonons and tunnel from the upper set of Landau levels to the lower one. As a result the relaxation rate exhibits giant magnetophonon oscillations whose amplit ude at strong magnetic fields is larger than the zero-field value by o ne to two orders of magnitude. Moreover, the rate shows oscillations a s function of DELTA(T). Collision broadening and phonon dispersion are taken into account.