Photoluminescence detected doublet structure in the integer and fractionalquantum Hall regime

The results of polarized magneto-photoluminescence measurements on a high m obility modulation-doped GaAs/AlGaAs single-heterojunction are presented. A well resolved doublet structure emerges from the neutral exciton peak over a wide magnetic field range for filling factors 2 > nu > 1/6. The energy s eparation between the peaks is less than the calculated energy for the form ation of the magneto-roton minima of the charged density waves that occurs in the fractional quantum Hall effect limit. However, the peaks display int ensity oscillations at various integer and fractional filling factors that are interrelated and depend on polarization. (C) 1999 Elsevier Science Ltd. All rights reserved.