Anderson-Fano resonance and shake-up processes in the magnetophotoluminescence of a two-dimensional electron system

We report an anomalous doublet structure and low-energy satellite in the magnetophotoluminescence spectra of a two-dimensional electron system. The doublet structure moves to higher energy with increasing magnetic field and is most prominent at odd filling factors n55 and n53. The lower-energy satellite peak tunes to lower energy for increasing magnetic fields between n56 and n52. These features occur at energies below the fundamental band of recombination originating from the lowest Landau level and display striking magnetic field and temperature dependence that indicates a many-body origin. Drawing on a recent theoretical description of Hawrylak and Potemski @Phys. Rev. B 56, 12 386 ~1997!#, we show that distinct mechanisms are responsible for each feature. @S0163-1829~98!51516-0#