Edge magnetoplasmon excitations in a Quantum Dot in high magnetic fields

TL;DR

This paper studies edge magnetoplasmon excitations in quantum dots under high magnetic fields, analyzing their dispersion, dependence on magnetic field and size, and the behavior of the breathing mode approaching cyclotron frequency.

Contribution

It provides a detailed analysis of edge magnetoplasmon modes in finite quantum dots, including their multipolarities and energy dependence on magnetic field and size, using a sum-rule approach.

Findings

Edge modes decrease in energy with increasing magnetic field.

Modes become gapless in the bulk limit.

Breathing mode energy approaches cyclotron frequency.

Abstract

We investigate the collective magnetoplasmon excitations in a quantum dot containing finite number of electrons in the high magnetic field limit. We consider the electrons in the lowest Landau level and neglect mixing between the higher Landau levels. The dispersion relation of these edge modes are estimated following the energy weighted sum-rule approach. In this finite size system the edge magnetoplasmon modes have different multipolarities (or angular momemtum l). Their dependence on the magnetic field and on the system size is investigated. With increasing magnetic field, energy of these collective modes decreases and in the bulk limit they become gapless. We also consider the breathing mode of a dot in the presence of a strong magnetic field, and the energy of this mode approaches the cyclotron frequency $\hbar \omega_{c}$.