ELECTRON-ELECTRON INTERACTIONS IN EMISSION FROM A 2-DIMENSIONAL ELECTRON-GAS IN QUANTIZING MAGNETIC-FIELDS

The recombination of a thermalized valence band hole with a high quali ty two-dimensional electron gas shows clear spectral features due to e lectron-electron interactions in the regime of the integer quantum Hal l effect. A pronounced doubletlike emission observed around odd fillin g factors nu = 3,5 is attributed to the destructive interferences betw een the optically created hole in the Fermi sea and the continuous spe ctrum 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.