Anisotropic spectra of magnetoplasmons in wide parabolic quantum-well systems

Anisotropic intrasubband magnetoplasmons of an electron gas in a wide parabolic quantum well are obtained by using a method within the framework of the random-phase approximation. The symmetries and shapes of the various perturbed Hartree potentials along the confining direction at B=0 are found analytically. Anisotropy of the intrasubband modes in the presence of a longitudinal magnetic field perpendicular to the confinement direction is revealed and explained. We also make a striking prediction that a strong longitudinal magnetic field can give rise to an additional one-dimensional-like undamped intrasubband magnetoplasmon mode which is well within the experimentally accessible range.