Magnetoplasmon excitations in arrays of circular and noncircular quantum dots

TL;DR

This study investigates magnetoplasmon excitations in arrays of circular and noncircular quantum dots, revealing how local symmetry breaking and interdot interactions influence collective modes, with results aligning with recent FIR experiments.

Contribution

It provides a detailed analysis of how local perturbations and interdot Coulomb interactions affect magnetoplasmon modes in quantum dot arrays, highlighting symmetry effects and mode coupling.

Findings

Local symmetry reduction causes mode coupling and anticrossings.

Interdot Coulomb interactions are significant only at small separations.

Results agree with recent FIR transmission experimental data.

Abstract

We have investigated the magnetoplasmon excitations in arrays of circular and noncircular quantum dots within the Thomas-Fermi-Dirac-von Weizs\"acker approximation. Deviations from the ideal collective excitations of isolated parabolically confined electrons arise from local perturbations of the confining potential as well as interdot Coulomb interactions. The latter are unimportant unless the interdot separations are of the order of the size of the dots. Local perturbations such as radial anharmonicity and noncircular symmetry lead to clear signatures of the violation of the generalized Kohn theorem. In particular, the reduction of the local symmetry from SO(2) to $C_4$ results in a resonant coupling of different modes and an observable anticrossing behaviour in the power absorption spectrum. Our results are in good agreement with recent far-infrared (FIR) transmission experiments.