MECHANISM OF SHAKEUP PROCESSES IN THE PHOTOLUMINESCENCE OF A 2-DIMENSIONAL ELECTRON-GAS AT HIGH MAGNETIC-FIELDS

We observe shakeup processes in the photoluminescence spectra of a two -dimensional electron gas in a GaAs/AlxGa1-xAs quantum well at high ma gnetic fields. We find that when the electrons occupy only the lowest Landau level these processes are strongly suppressed. We show that thi s behavior can be accounted for by first-principles calculations. We u se the same considerations to explain the giant intensity of the shake up line, which appears just below the main luminescence line.