PL spectroscopy of Fermi electrons in regime of the quantum Hall effect

The influence of the interlayer coupling on formation of the quantized Hall phase at the filling factor ν=2 was studied in the multilayer GaAs/AlGaAs heterostructures. The disorder broaden Gaussian photoluminescence line due to the localized electrons was found in the quantized Hall phase of the isolated multi-quantum well structure. On the other hand, the quantized Hall phase of the weakly-coupled multilayers emitted an asymmetrical line similar to that one observed in the metallic electron systems. We demonstrated that the observed asymmetry indicates a formation of the Fermi surface in the quantized Hall phase of the multilayer electron system due to the interlayer percolation. A sharp decrease of the single-particle scattering time associated with the extended states on the Fermi surface was observed at the filling factor ν=2.