Acoustic plasmons in graphene sandwiched between two metallic slabs

TL;DR

This paper investigates how metallic slabs influence graphene's electron collective excitations, revealing conditions for acoustic plasmons with linear dispersion and dependence on slab geometry.

Contribution

It demonstrates the emergence of acoustic plasmons in graphene sandwiched between metallic slabs and analyzes their dispersion relations under various conditions.

Findings

Perfect conductors induce linear dispersion of plasmons.

Acoustic plasmons depend on the distance between slabs and graphene.

Conditions for acoustic plasmons in generic slabs are identified.

Abstract

We study the effect of two metallic slabs on the collective dynamics of electrons in graphene positioned between the two slabs. We show that if the slabs are perfect conductors the plasmons of graphene display a linear dispersion relation. The velocity of these acoustic plasmons crucially depends on the distance between the two metal gates and the graphene sheet. In the case of generic slabs, the dispersion relation of graphene plasmons is much more complicated but we find that acoustic plasmons can still be obtained under specific conditions.