Hydrodynamics in graphene: Linear-response transport

TL;DR

This paper develops a hydrodynamic framework for understanding transport in graphene, revealing how macroscopic currents and magnetoresistance behave in different sample geometries and doping conditions.

Contribution

It introduces a three-mode hydrodynamic model derived from quantum kinetic equations to describe transport in graphene, including magnetoresistance and drag phenomena.

Findings

Classical magnetoresistance depends on sample geometry and relaxation processes.

In small samples, inhomogeneous currents cause linear magnetoresistance.

The theory explains giant magnetodrag and Hall drag in doped graphene.

Abstract

We develop a hydrodynamic description of transport properties in graphene-based systems which we derive from the quantum kinetic equation. In the interaction-dominated regime, the collinear scattering singularity in the collision integral leads to fast unidirectional thermalization and allows us to describe the system in terms of three macroscopic currents carrying electric charge, energy, and quasiparticle imbalance. Within this "three-mode" approximation we evaluate transport coeffcients in monolayer graphene as well as in double-layer graphene-based structures. The resulting classical magnetoresistance is strongly sensitive to the interplay between the sample geometry and leading relaxation processes. In small, mesoscopic samples the macroscopic currents are inhomogeneous which leads to linear magnetoresistance in classically strong fields. Applying our theory to double-layer graphene-based systems, we provide microscopic foundation for phenomenological description of giant magnetodrag at charge neutrality and find magnetodrag and Hall drag in doped graphene.