Evidence of interlayer interaction in magnetoluminescence spectra of electron bilayers

Magnetoluminescence studies in electron bilayers reveal the hallmarks of the even denominator and other quantum Hall states in the intensities and energies of the interband optical recombination lines. In the presence of a small tunneling gap between the layers the magneto-optical emission from the lowest antisymmetric subband, not populated in a single-electron picture, displays maxima at filling factors 1 and 2/3. These findings uncover a loss of pseudospin polarization, where the pseudospin describes the layer index degree of freedom that is linked to an anomalous population of the antisymmetric level due to excitonic correlations. The results demonstrate a new realm to probe the impact of interlayer Coulomb interaction in quantum Hall bilayers.