Photoluminescence of a high mobility 2DEG in the fractional quantum Hall effect regime
10 April 2007
The magneto-PL spectra of modulation-doped, ultra-high mobility GaAs/AlGaAs single heterojunctions (HJs) were studied under a perpendicularly applied magnetic field up to 33 T and at temperatures of 0.3 and 1.2 K. The spectra show remarkable intensity redistribution between free (bulk) exciton and 2DEG-hole PL channels occurring at electron filling factors, v = 2 and 1. At 0.3 K, significant 2DEG-hole PL spectral changes axe observed near v =2/3 and 1/3. Several heterojunctions with 2DEG density in the range of n(2D) = (1 - 2.7) - 10(11) cm(-2) display similar features. These spectral peculiarities are attributed to the modification of the 2DEG energy spectrum caused by the e-e interaction, in particular, the recombination of valence hole with the composite (fractionally-charged) particles of the magnetized 2DEG.