Magnetoplasmons of a two-dimensional electron gas with equilibrium density inhomogeneities

Interedge magnetoplasmons are a class of magnetoplasmons localized at the boundary defined by two bidimensional metallic domains with different equilibrium densities. They reduce to the usual edge magnetoplasmons when one of the equilibrium densities is exactly zero. The application of a hydrodynamical theory to a disk-shaped electron fluid with a central inhomogeneity reveals the existence of both edge and interedge magnetoplasmons in the high magnetic field regime, whose frequency decreases with magnetic field. If the equilibrium density of the central inhomogeneity is greater than the equilibrium density of the ring area that surrounds it, both magnetoplasmons have the same symmetry and anticross strongly. In the low-field regime, the interedge magnetoplasmon exhibits a cyclotron resonance like dependence on the magnetic field. The calculations are in qualitative agreement with recent experiments performed in the extremely high-field regime and suggest new experiments at lower fields and/or different systems.