Nonlinear density waves on graphene electron fluids

TL;DR

This paper investigates nonlinear density waves in graphene electron fluids, deriving equations that describe solitary waves and shocks, with implications for future plasmonic device applications.

Contribution

It introduces a hydrodynamic model incorporating Bohm potential and viscosity, deriving novel nonlinear wave equations for graphene electron flows.

Findings

Derivation of a dissipative Kadomtsev-Petviashvili equation for 2D flow

Identification of unstable modes in nonlinear wave equations

Potential for wave excitation in graphene plasmonic devices

Abstract

In graphene, where the electron-electron scattering is dominant, electrons collectively act as a fluid. This hydrodynamic behaviour of charge carriers leads to exciting nonlinear phenomena such as solitary waves and shocks, among others. In the future, such waves might be exploited on plasmonic devices, either for modulation or signal propagation along graphene waveguides. We study the nature of nonlinear perturbations by performing the reductive perturbation method on the hydrodynamic description of graphene electrons, taking into consideration the effect of Bohm quantum potential and odd viscosity. Thus, deriving a dissipative Kadomtsev-Petviashvili equation for the bidimensional flow as well as its unidimensional limit in the form of Korteweg-de Vries-Burgers. The stability analysis of these equations unveils the existence of unstable modes that can be excited and launched through graphene plasmonic devices.