Plasmonic Excitations in Tight-Binding Nanostructures

TL;DR

This paper investigates how the shape, electron filling, and external field frequency influence plasmonic excitations in atomic nanostructures using a quantum-mechanical tight-binding approach, enabling tailored localized responses.

Contribution

It introduces a fully quantum-mechanical method to analyze and control collective electromagnetic responses in nanostructures based on their geometry and electronic properties.

Findings

System shape and electron filling significantly affect resonance properties.

External frequency controls the spatial and spectral characteristics of excitations.

Designing nanostructure geometry allows for localized collective excitations.

Abstract

We explore the collective electromagnetic response in atomic clusters of various sizes and geometries. Our aim is to understand, and hence to control, their dielectric response, based on a fully quantum-mechanical description which captures accurately their relevant collective modes. The electronic energy levels and wave functions, calculated within the tight-binding model, are used to determine the non-local dielectric response function. It is found that the system shape, the electron filling and the driving frequency of the external electric field strongly control the resonance properties of the collective excitations in the frequency and spatial domains. Furthermore, it is shown that one can design spatially localized collective excitations by properly tailoring the nanostructure geometry.