Guided plasmons in graphene p-n junctions

TL;DR

This paper develops a hydrodynamic theory of guided plasmon modes in graphene p-n junctions, showing controllable dispersion relations and magnetoplasmon excitations, highlighting graphene's potential in nanoplasmonics.

Contribution

It introduces a theoretical framework for guided plasmons in graphene p-n junctions, including effects of magnetic fields and external control, advancing understanding of graphene-based nanoplasmonic devices.

Findings

Plasmon dispersion follows   q^{1/4} for small wavelengths.

External electric fields can control plasmon frequency, velocity, and propagation direction.

Magnetic fields introduce gapless magnetoplasmon excitations.

Abstract

Spatial separation of electrons and holes in graphene gives rise to existence of plasmon waves confined to the boundary region. Theory of such guided plasmon modes within hydrodynamics of electron-hole liquid is developed. For plasmon wavelengths smaller than the size of charged domains plasmon dispersion is found to be \omega ~ q^(1/4). Frequency, velocity and direction of propagation of guided plasmon modes can be easily controlled by external electric field. In the presence of magnetic field spectrum of additional gapless magnetoplasmon excitations is obtained. Our findings indicate that graphene is a promising material for nanoplasmonics.