Photoluminescence from fractional quantum Hall systems: Role of separation between electron and hole layers

of these states rather than the original correlations of the 2DEG. At d.2l, depending on the filling factor n, the hole either decouples from the 2DEG to form an ‘‘uncorrelated’’ state h or binds one or two Laughlin quasielectrons ~QE’s ! to form fractionally charged excitons hQE or hQE2. The strict optical selection rules for bound states are formulated, and the only optically active ones turn out to be h, hQE* ~an excited state of the dark hQE), and hQE2. The ‘‘anyon exciton’’ hQE3 suggested in earlier studies is neither stable nor radiative at any value of d. The critical dependence of the stability of different states on the presence of QE’s in the 2DEG explains the observed anomalies in the PL spectrum at n5 1 3 and 2 3 .