Effective screening and the plasmaron bands in Graphene

TL;DR

This paper investigates how the dielectric environment affects electron-plasmon coupling in graphene, using spectroscopy to analyze plasmaron bands and exploring independent control of plasmaronic properties for device applications.

Contribution

It provides experimental comparison of screening effects in graphene on different substrates and demonstrates independent manipulation of plasmaron and electronic properties.

Findings

Screening strength varies with substrate dielectric constant.

Plasmaron bands are separable from hole bands in spectroscopy.

Electronic and plasmaronic properties can be independently tuned.

Abstract

Electron-plasmon coupling in graphene has recently been shown to give rise to a "plasmaron" quasiparticle excitation. The strength of this coupling has been predicted to depend on the effective screening, which in turn is expected to depend on the dielectric environment of the graphene sheet. Here we compare the strength of enviromental screening for graphene on four different substrates by evaluating the separation of the plasmaron bands from the hole bands using Angle Resolved PhotoEmission Spectroscopy. Comparison with G0W-RPA predictions are used to determine the effective dielectric constant of the underlying substrate layer. We also show that plasmaron and electronic properties of graphene can be independently manipulated, an important aspect of a possible use in "plasmaronic" devices.