Hydrodynamic theory of transport in doped graphene

TL;DR

This paper develops a hydrodynamic model to analyze non-linear dc transport in doped graphene, revealing velocity saturation due to phonon interactions and emphasizing the importance of electron-electron interactions for accurate resistivity predictions.

Contribution

It introduces a hydrodynamic framework for graphene transport that incorporates phonon interactions and electron-electron effects, providing new insights into velocity saturation and resistivity behavior.

Findings

Velocity saturates at ~10^7 cm/s in clean samples.

Saturation results from interactions with phonons.

Electron-electron interactions increase high-temperature resistivity.

Abstract

We study non-linear dc transport in graphene using a hydrodynamic approach and conclude that in clean samples the drift velocity saturates at a weakly density-dependent value v_{sat} ~ 10^7 cm/s. We show that saturation results from the interactions between graphene's Dirac quasi-particles and both acoustic and optical phonons. Saturation is accompanied by substantial electron heating and is not reached at realistic driving fields in moderately or strongly disordered samples. We find that it is essential to account for interactions among graphene's Dirac quasi-particles, which increase the linear response resistivity at high temperatures or low densities.