The shear viscosity of interacting graphene

TL;DR

This paper investigates the shear viscosity of interacting graphene using phenomenological and microscopic models, revealing that collective modes significantly contribute to viscosity, which impacts electronic transport understanding.

Contribution

It provides a combined phenomenological and microscopic analysis of graphene's shear viscosity, highlighting the importance of collective modes in the viscosity calculation.

Findings

Collective modes significantly contribute to shear viscosity.

Excellent agreement between phenomenological and microscopic models.

Implications for other Dirac materials and electronic transport.

Abstract

One of the hallmark properties of fluids is their shear viscosity which is, among other things, responsible for parabolic flow profiles through narrow channels. In recent years, there has been a growing number of observations of said flow profiles in electronic transport measurements in a variety of material systems, most notably in graphene. In this paper, we investigate the shear viscosity of interacting graphene from a theoretical point of view. We study both a phenomenological as well as a microscopic model and find excellent agreement between the two. Our main finding is collective modes make a sizeable contribution to the viscosity that can equal or even outweigh the electronic contribution that is usually assumed dominant. We comment on how this finding carries over to systems beyond graphene and related Dirac materials.