Graphene plasmon polaritons: Substrate effects and nonlocal response

TL;DR

This theoretical study investigates how substrate effects and nonlocal electron response influence graphene plasmon polaritons, revealing that nonlocal effects introduce substrate dependence and remove dispersion singularities.

Contribution

It provides a comparative analysis of local and nonlocal models, showing nonlocal responses lead to substrate-dependent GPPs and eliminate dispersion singularities.

Findings

Local response predicts substrate-independent GPP frequency.

Nonlocal response introduces substrate dependence.

Nonlocal effects remove dispersion singularities.

Abstract

This paper is withdrawn by the authors. We theoretically examine graphene plasmon polaritons (GPP) supported by a sheet of graphene sandwiched between two dielectric media. The influence of the dielectric environment on GPP's is studied within local and nonlocal descriptions of graphene's conductivity. We demonstrate that a local-response approximation invariably leads, counter-intuitively, to a substrate-independent surface plasmon frequency. On the other hand, the nonlocal description of the electron gas allows the presence of non-vertical inter-band transitions which changes the results qualitatively: the GPP's now depend on the surroundings, and the singularity in the local GPP dispersion relation is removed.