Magnetoplasmons and cyclotron resonance in a two-dimensional electron gas

Cyclotron resonancen (CR) transitions in quasi two-dimensional electron gas (2DEG) are known to involve magnetoplasmons (MP) dispersion. It has been recently [1] possible to derive in the frame of the MP picture, assuming the Hartree-Fock approximation, the magneto conductivity response of such systems for any value of the filling factor $\nu $ and including non-parabolicity effects. As compared to the one-electron picture, the MP theory predicts specific behavior of the response concerning both the oscillator strength as well as the energy variation of the CR transitions as a function of $\nu $. These predictions are confronted to absolute magneto-transmission results obtained on high mobility 2DEG embedded in GaAs quantum wells. It is shown that the MP theory reproduces quite well the experimental findings for 2n+1$<\nu <$ 2n+2 whereas clear discrepancies appear for 2n$<\nu <$ 2n+1. The possible origin of these discrepancies are discussed. [1] Yu. A. Bychkov and G. Martinez, Phys. Rev. B\textbf{72}, 195328 (2005)