Influence of shape of quantum dots on their far-infrared absorption

TL;DR

This study explores how the shape of quantum dots influences their far-infrared absorption properties under magnetic fields, revealing complex mode interactions due to shape deviations from circular symmetry.

Contribution

It introduces a model calculation analyzing non-circular and doughnut-shaped quantum dots, highlighting shape-dependent effects on absorption spectra beyond the generalized Kohn theorem.

Findings

Shape deviations cause mixing of absorption modes.

Results align with experimental observations.

Non-circular shapes alter collective excitation modes.

Abstract

We investigate the effects of the shape of quantum dots on their far-infrared absorption in an external magnetic field by a model calculation. We focus our attention on dots with a parabolic confinement potential deviating from the common circular symmetry, and dots having circular doughnut shape. For a confinement where the generalized Kohn theorem does not hold we are able to interprete the results in terms of a mixture of a center-of-mass mode and collective modes reflecting an excitation of relative motion of the electrons. The calculations are performed within the time-dependent Hartree approximation and the results are compared to available experimental results.