Plasmon Excitations for Encapsulated Graphene

TL;DR

This paper presents an analytical approach to calculate plasmon dispersion in encapsulated graphene, considering nonlocal effects and revealing multiple plasmon modes in a sandwich system.

Contribution

It introduces a new analytical formulation for plasmon dispersion in encapsulated graphene, accounting for nonlocal effects and complex mode interactions.

Findings

Identification of linear and depolarization plasmon modes

Density plots showing mode dispersion and shifts

Nonlocal effects significantly influence plasmon spectrum

Abstract

We have developed an analytical formulation to calculate the plasmon dispersion relation for a two-dimensional layer which is encapsulated within a narrow spatial gap between two bulk half-space plasmas. This is based on a solution of the inverse dielectric function integral equation within the random-phase approximation (RPA). We take into account the nonlocality of the plasmon dispersion relation for both gapped and gapless graphene as the sandwiched two-dimensional (2D) semiconductor plasma. The associated nonlocal graphene plasmon spectrum coupled to the "sandwich" system is exhibited in density plots, which show a linear mode and a pair of depolarization modes shifted from the bulk plasma frequency.