Engineering plasmon modes and their loss in armchair graphene nanoribbons by selected edge-extended defects

TL;DR

This paper theoretically investigates how edge modifications in armchair graphene nanoribbons can be used to engineer and tune novel plasmon modes, including magnetoplasmon-like excitations, without external magnetic fields.

Contribution

It introduces a method to control and design plasmon modes in AGNRs through specific edge-extended defects, revealing their relationship with flat bands and collective excitations.

Findings

Edge modifications enable tuning of plasmon modes.

Novel collective excitations are linked to flat bands.

Plasmon modes resemble magnetoplasmons without magnetic fields.

Abstract

The effect of edge modification of armchair graphene nanoribbons (AGNRs) on the collective excitations are theoretically investigated. The tight-binding method is employed in conjunction with the dielectric function. Unconventional plasmon modes and their association with the flat bands of the specially designed AGNRs are thoroughly studied. We demonstrate the robust relationship between the novel collective excitations and both the type and period of the edge modification. Additionally, we reveal that the main features displayed in the (momentum, frequency)-phase diagrams for both single-particle and collective excitations of AGNRs can be efficiently tuned by edge-extended defects. Our obtained plasmon modes are found to be analogous to magnetoplasmons associated with collective excitations of Landau-quantized electrons. This work provides a unique way to engineer discrete magnetoplasmon-like modes of AGNRs in the absence of magnetic field.