Inelastic carrier lifetime in a coupled graphene electron-phonon system: Role of plasmon-phonon coupling

摘要

We calculate the inelastic scattering rates and the hot electron inelasticmean free paths for both monolayer and bilayer graphene on a polar substrate.We study the quasiparticle self-energy by taking into account bothelectron-electron and electron-surface optical (SO) phonon interactions. Inthis calculation the leading order dynamic screening approximation (G$_0$Wapproximation) is used to obtain the quasiparticle self-energy by treatingelectrons and phonons on an equal footing. We find that the strong couplingbetween the SO phonon and plasmon leads to a new decay channel for thequasiparticle through the emission of the coupled mode, and gives rise to anabrupt increase in the scattering rate, which is absent in the uncoupledsystem. In monolayer graphene a single jump in the scattering rate occurs,arising from the emission of the low energy branch of the coupledplasmon-phonon modes. In bilayer graphene the emission of both low and highenergy branches of the coupled modes contributes to the scattering rate andgives rise to two abrupt changes in the scattering rate. The jumps in thescattering rate can be potentially used in the hot electron device such asswitching devices and oscillators.