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 perpendicular magentic field. When the energy splitting ${\mathrm{\Delta }}_{\mathit{T}}$, between 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 amplitude at strong magnetic fields is larger than the zero-field value by one to two orders of magnitude. Moreover, the rate shows oscillations as a function of ${\mathrm{\Delta }}_{\mathit{T}}$. Collision broadening and phonon dispersion are taken into account.