ANISOTROPIC SPECTRA OF MAGNETOPLASMONS IN WIDE PARABOLIC QUANTUM-WELLSYSTEMS

Anisotropic intrasubband magnetoplasmons of an electron gas in a wide parabolic quantum well are obtained by using a method within the frame work of the random-phase approximation. The symmetries and shapes of t he 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 co nfinement 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 magnetoplasm on mode which is well within the experimentally accessible range.