Low-temperature electron magnetotransport in single GaAs quantum wells with two populated subbands is studied at large filling factors. Magneto-intersubband (MIS) and acoustic-phonon-induced oscillations of dissipative resistance are found to be coexisting but interfering substantially with each other. The experiments show that amplitude of the MIS oscillations enhances significantly by phonons, indicating “constructive interference” between the electron-phonon scattering and the intersubband electron transitions. Temperature damping of the quantum oscillations is found to be related to broadening of Landau levels caused by considerable electron-electron scattering.

• Received 12 January 2010

DOI:https://doi.org/10.1103/PhysRevB.81.155322