Ab initio calculations of low-energy quasiparticle lifetimes in bilayer graphene

TL;DR

This paper uses first-principles calculations to analyze low-energy quasiparticle lifetimes in bilayer graphene, revealing linear energy dependence in undoped cases and non-linear effects with doping, aligning with experimental data.

Contribution

It provides the first ab initio calculation of quasiparticle lifetimes in bilayer graphene, including electron-electron interactions and doping effects.

Findings

Inverse lifetime scales linearly with energy in undoped bilayer graphene.

Decay rate in bilayer graphene is about three times larger than in monolayer graphene.

Doping introduces non-linear energy dependence due to acoustic plasmon decay channels.

Abstract

Motivated by recent experimental results we calculate from first-principles the lifetime of low-energy quasiparticles in bilayer graphene (BLG). We take into account the scattering rate arising from electron-electron interactions within the $GW$ approximation for the electron self-energy and consider several p-type doping levels ranging from $0$ to $\rho \approx 2.4\times 10^{12}$ holes/cm$^2$. In the undoped case we find that the average inverse lifetime scales linearly with energy away from the charge neutrality point, with values in good agreement with experiments. The decay rate is approximately three times larger than in monolayer graphene, a consequence of the enhanced screening in BLG. In the doped case, the dependence of the inverse lifetime on quasiparticle energy acquires a non-linear component due to the opening of an additional decay channel mediated by acoustic plasmons.