PLASMON EXCITATIONS IN NONDEGENERATE QUASI-ONE-DIMENSIONAL ELECTRON-SYSTEMS

The many-body dielectric formalism is applied for the laterally confin ed nondegenerate electron system over the liquid helium surface. The d ensity-density response function dependent on the wave number and freq uency for the multisubband quasi-one-dimensional (Q1D) system is evalu ated within the random-phase approximation for arbitrary values of wav e number and subband index. The spectra of both intrasubband and inter subband plasmons are obtained in the limit of small wave numbers and l ow temperatures, The intrasubband plasmon dispersion is almost soundli ke and similar to that of intrasubband plasmons in degenerate Q1D syst ems and in the QID electron chain. The intersubband mode is optical-li ke with frequency close to the one-electron frequency related to the l ateral parabolic confinement. Intra-and intersubband magnetoplasmon fr equencies are also derived. Our results are compared with recent spect roscopic experiment.