Electron-electron interactions in emission from a two-dimensional electron gas in quantizing magnetic fields

The recombination of a thermalized valence band hole with a high quality two-dimensional electron gas shows clear spectral features due to electron-electron interactions in the regime of the integer quantum Hall effect. A pronounced doubletlike emission observed around odd filling factors nu = 3,5 is attributed to the destructive interferences between the optically created hole in the Fermi sea and the continuous spectrum of spin wave excitations. Redshifts in the spectral position at nu similar to 1,2 reveal the competition between the interband Coulomb binding and the electron-electron interaction in the final state in a spatially separated electron and valence hole system.