Magnetoplasma spectra of two-dimensional electron rings

• Published in: Superlattices and microstructures 1995-01, Vol.17 (2), p.173-176
• Main Authors: Cui, H.L., Fessatidis, V., Kühn, O.
• Format: Article
• Language: English
• Subjects: Collective excitations (including excitons, polarons, plasmons and other charge-density excitations); Collective excitations (including plasmons and other charge-density excitations); Computational methods; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Electric charge; Electric excitation; Electronic structure and electrical properties of surfaces, interfaces, thin films and low-dimensional structures; Exact sciences and technology; Hydrodynamics; Magnetic field effects; Magnetic moments; Magnetic resonance; Physics; Semiconductor quantum dots; Spectroscopy; Surface and interface electron states
• ISSN: 0749-6036; 1096-3677
• DOI: 10.1006/spmi.1995.1033

A hydrodynamical approach is employed to study the collective excitations of a two-dimensional electron gas confined in a ring geometry, under a normal magnetic held. The theory predicts a rich spectrum of magnetoplasma excitations, with several branches of high- and low-frequency resonances. It is shown that the low-frequency resonances can be identified as edge magnetoplasmons localized at the inner and outer boundaries of the ring, exhibiting their characteristic antidot-like and dot-like features. The high-frequency resonances are essentially bulk two-dimensional magnetoplasmons. Our calculated magnetoplasma modes and their associated induced charge densities and dipole moments are compared with a recent experiment, and it is found that most of the experimentally observed features of the spectrum are accounted for with the present theory.