Optical Anomalies of the Two-Dimensional Electron Gas in the Extreme Magnetic Quantum Limit

Abstract
Band-gap optical recombination from the two-dimensional electron gas in GaAs-(Al,Ga)As quantum wells was measured in the regime of the fractional quantum Hall effect. New intrinsic emission lines emerge at the Landau-level filling factor ν1 and at ν<0.8. The anomaly near ν=1 is associated with changes in population of the lowest spin-split Landau level. The spectral doublet observed near ν=23 has a striking temperature dependence below T=2 K similar to the magnetoresistance ρxx associated with the many-body quantum fluid.