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 $\nu =3,5\mathrm{}$ 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 $\nu \sim 1,2$ 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.