Symmetry Breaking in Few Layer Graphene Films

TL;DR

This paper reviews methods for analyzing quasiparticle dynamics and layer-dependent properties in few-layer graphene films using ARPES, and argues against the existence of an energy gap at the Dirac point.

Contribution

It provides a detailed methodology for extracting physical parameters from ARPES data and presents arguments against an energy gap at the Dirac crossing in graphene.

Findings

Layer-dependent charge and potential can be extracted from ARPES.

The c-axis screening coefficient can be determined from spectral function measurements.

There is no evidence of an energy gap at the Dirac point in the studied graphene films.

Abstract

Recently, it was demonstrated that the quasiparticle dynamics, the layer-dependent charge and potential, and the c-axis screening coefficient could be extracted from measurements of the spectral function of few layer graphene films grown epitaxially on SiC using angle-resolved photoemission spectroscopy (ARPES). In this article we review these findings, and present detailed methodology for extracting such parameters from ARPES. We also present detailed arguments against the possibility of an energy gap at the Dirac crossing ED.