Correlations, Plasmarons, and Quantum Spectral Function in Bilayer Graphene

TL;DR

This paper investigates the many-body electron interactions in doped bilayer graphene, revealing Fermi liquid behavior and plasmaron features in the spectral function, with detailed calculations of quasiparticle properties.

Contribution

It provides a theoretical analysis of electron-electron interactions in bilayer graphene using RPA, highlighting plasmaron peaks and quasiparticle characteristics.

Findings

Fermi liquid behavior confirmed near the Fermi surface

Presence of broad plasmaron peaks away from the Fermi surface

Calculated quasiparticle residue and effective mass as functions of carrier density

Abstract

We theoretically study the many-body effects of electron electron interaction on the single particle spectral function of doped bilayer graphene. Using random phase approximation, we calculate the real and imaginary part of the self-energy and hence the spectral function. The spectral function near the Fermi surface shows the usual quasiparticle peak, establishing doped bilayer graphene, in contrast to the unstable neutral system, to be a Fermi liquid. Away from the Fermi surface, an additional broad plasmaron peak is visible in the spectral function. From the low energy behaviour of the self-energy we calculate the quasiparticle residue and the effective mass of the quasiparticles as a function of carrier density. We present results for both the on-shell and the off-shell approximation for the quasiparticle renormalization.