Measurement of the magnetoplasmon density of states in the radiative recombination spectrum of symmetrically doped quantum wells

Photoluminescence spectra of symmetrically and asymmetrically doped quantum wells in highly mobile GaAs/AlGaAs heterostructures have been investigated. Additional maxima have been found in the magnetoplasmon replica of the main optical transition from the conduction band to the heavy hole subband of the valence band of a symmetrically doped quantum well at the electron filling factor $\nu = 1$. Maxima in the photoluminescence spectrum are attributed to Van Hove singularities in the magnetoplasmon density of states as a function of the energy. The correlation of the observed features in the photoluminescence spectrum with known transport and optical studies has been discussed.