Core-level spectra from bilayer graphene

TL;DR

This paper derives and analyzes core-level spectra for doped bilayer graphene, comparing it with monolayer spectra and exploring the effects of doping and inter-band excitations on collective modes.

Contribution

It provides a detailed theoretical derivation of core-level spectra for doped bilayer graphene and compares these with monolayer results, highlighting modifications in collective mode dispersions.

Findings

Core-level spectra for various doping levels in bilayer graphene are computed.

Comparison shows differences between bilayer and monolayer spectra.

Dispersion of collective modes is altered in the bilayer system.

Abstract

We derive core-level spectra for doped free-standing bilayer graphene. Numerical results are presented for all nine combinations of the doping concentrations $10^{12}\rm{cm}^{-2}$, $10^{13}\rm{cm}^{-2}$, and $10^{14}\rm{cm}^{-2}$ in the two graphene sheets and we compare the results to the reference spectra for monolayer graphene. We furthermore discuss the spectrum of single-particle inter-band and intra-band excitations in the $\omega q$-plane, and show how the dispersion curves of the collective modes are modified in the bilayer system.