Magnetoplasmons of the two-dimensional electron system in a parabolic channel over liquid helium

Magnetoplasmon waves of the nondegenerate two-dimensional electron system confined in a parabolic channel over liquid helium are studied in the ultra quantum limit (only the lowest spin-split Landau level is occupied) and strong magnetic fields. It is shown that the dispersion relations and spatial structures have the characteristic scale View the MathML source, where Ω is the confinement frequency and ℓ0 is the magnetic length. We find a rich spectrum of low-frequency excited acoustical modes whose phase velocities exhibit anticrossings as a function of the metal gate distance d, for d⪡ℓT. It is shown that appearance of the anticrossings has essentially a quantum nature combined with the effect of the electron–electron interaction. In order to be able to discuss the conditions to detect the modes we determine the mode dissipation and compare our results with experimental data.