Magnetoplasma excitations in parabolic quantum wells: Hydrodynamic model

We employ a classical hydrodynamic model to study the magnetoplasma excitations of a slab of electron fluid confined in one direction by a parabolic potential, in a tilted magnetic field. The electron gas is treated as a classical charge fluid with an internal pressure p∝(n-${\mathit{n}}_{\mathit{c}}$), when n is the number density of electrons and ${\mathit{n}}_{\mathit{c}}$ is a density at which the pressure vanishes. Linearizing the dynamical equations and neglecting retardation effects, we calculate the dispersion of the magnetoplasmon frequencies as a function of the in-plane wave vector q. We study the dependence of this dispersion on the strength and tilt angle of the applied magnetic field and on the parameter ${\mathit{n}}_{\mathit{c}}$, and show that the q=0 frequencies that we calculate help in understanding optical experiments on imperfect parabolic wells.