A classical hydrodynamic approach is used to calculate the magnetoplasma excitations of two vertically coupled electron dots. The electrons are confined by different parabolic potentials in which case Kohn’s theorem is no longer valid. The equilibrium density profiles of the electrons in both dots are calculated as a function of the interdot distance. We find that for unequal confinement of the two dots the electron density in one of the dots becomes ringlike. The electron densities are then used to obtain the magnetoplasma frequencies. The oscillator strengths are calculated, and we find that other than the center-of-mass modes can be excited due to the electron-electron interaction.

• Received 4 December 1997

DOI:https://doi.org/10.1103/PhysRevB.57.13039