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

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 ρ≈2.4×1012 holes/cm2. 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.