Large oscillations in the photoluminescence spectra of a GaAs quantum well in external magnetic fields: A direct measurement of charge transfer in an electron bilayer system

Photoluminescence studies of a wide asymmetric quantum well hosting two strongly coupled electron layers demonstrate unambiguously how such a system deforms itself due to interlayer charge transfer in a quantizing magnetic field thus manifesting its overall single-layer appearance. The charge distribution inside the quantum well is balanced for total filling factor nu=4N (N integer), while it is imbalanced at most for nu=4N+2. The intersubband energy oscillates enormously with the applied magnetic field and reaches values as large as the electron cyclotron energy for filling factors 4N.