Magnetoplasma excitations in anharmonic electron dots

We have used a classical hydrodynamic approach to study the magnetoplasma excitations in electron dots. The electrons are assumed to be confined within a plane by an anharmonic potential having circular symmetry. As a necessary first step, we develop a general procedure for determining the equilibrium electron distribution within the dot. This information is then used in the hydrodynamic analysis to yield a generalized eigenvalue problem for the magnetoplasma frequencies. Detailed applications are made to dots defined by a parabolic confining potential with a quartic radial perturbation. Contact with experiment is achieved by means of the calculated power absorption, which is found to be in good agreement with the observed far-infrared transmission spectra. In particular, the hydrodynamic model provides an explanation of the weak satellite, observed to track the high-frequency center-of-mass mode, in terms of the coupling of parabolic modes induced by the potential anharmonicity.