Double-layer graphene and topological insulator thin-film plasmons

TL;DR

This paper analyzes the collective plasmon modes in coupled Dirac systems like topological insulator thin films and graphene layers, revealing that bulk screening suppresses observable acoustic modes.

Contribution

It provides numerical and analytical insights into optical and acoustic plasmons in coupled Dirac materials, highlighting the impact of dielectric screening on mode observability.

Findings

TI acoustic modes are likely unobservable due to screening

Optical modes are present and characterized

Coupled graphene and TI systems exhibit distinct plasmon behaviors

Abstract

We present numerical and analytical results for the optical and acoustic plasmon collective modes of coupled massless-Dirac two-dimensional electron systems. Our results apply to topological insulator (TI) thin films and to two graphene sheets separated by a thin dielectric barrier layer. We find that because of strong bulk dielectric screening TI acoustic modes are locked to the top of the particle-hole continuum and therefore probably unobservable.