Temperature dependent resistivity in bilayer graphene due to flexural phonons

TL;DR

This study investigates how flexural phonons affect the temperature-dependent electrical resistivity in doped suspended bilayer graphene, revealing similarities to monolayer behavior and highlighting the impact of strain and electronic structure.

Contribution

It provides a detailed analysis of electron-phonon interactions in bilayer graphene, showing how flexural phonons influence resistivity and mobility, with new insights into quantitative differences from monolayer graphene.

Findings

Flexural phonons dominate resistivity without strain.

Tension suppresses flexural phonon contribution.

Room temperature mobility is higher in bilayer than monolayer graphene.

Abstract

We have studied electron scattering by out-of-plane (flexural) phonons in doped suspended bilayer graphene. We have found the bilayer membrane to follow the qualitative behavior of the monolayer cousin. In the bilayer, different electronic structure combine with different electron-phonon coupling to give the same parametric dependence in resistivity, and in particular the same temperature $T$ behavior. In parallel with the single layer, flexural phonons dominate the phonon contribution to resistivity in the absence of strain, where a density independent mobility is obtained. This contribution is strongly suppressed by tension, and in-plane phonons become the dominant contribution in strained samples. Among the quantitative differences an important one has been identified: room $T$ mobility in bilayer graphene is substantially higher than in monolayer. The origin of quantitative differences has been unveiled.