# Transport in bilayer graphene near charge neutrality: Which scattering mechanisms are important?

## TL;DR

This paper uses the quantum Boltzmann equation to analyze transport in bilayer graphene near charge neutrality, revealing the significant role of phonon scattering at low temperatures and validating a two-fluid hydrodynamic model.

## Contribution

It demonstrates that phonon scattering is important below 40K and introduces a two-fluid hydrodynamic model that accurately predicts transport properties.

## Key findings

- Phonon scattering is crucial below 40K.
- Electron-electron interactions dominate over phonons.
- The two-fluid model matches full quantum Boltzmann results.

## Abstract

Using the semiclassical quantum Boltzmann equation (QBE), we numerically calculate the DC transport properties of bilayer graphene near charge neutrality. We find, in contrast to prior discussions, that phonon scattering is crucial even at temperatures below 40K. Nonetheless, electron-electron scattering still dominates over phonon collisions allowing a hydrodynamic approach. We introduce a simple two-fluid hydrodynamic model of electrons and holes interacting via Coulomb drag and compare our results to the full QBE calculation. We show that the two-fluid model produces quantitatively accurate results for conductivity, thermopower, and thermal conductivity.