High Van Hove singularity extension and Fermi velocity increase in epitaxial graphene functionalized by gold clusters intercalation

TL;DR

This study demonstrates that gold cluster intercalation in epitaxial graphene on SiC(0001) preserves linear dispersion, enhances Fermi velocity, and extends Van Hove singularities without charge transfer, revealing new effects of intercalants on graphene's electronic structure.

Contribution

It shows that gold intercalation extends Van Hove singularities and increases Fermi velocity in epitaxial graphene without charge transfer, providing new insights into intercalant effects.

Findings

Fermi velocity increases with gold intercalation.

Van Hove singularities are strongly extended.

Linear dispersion of quasiparticles is preserved.

Abstract

Gold intercalation between the buffer layer and a graphene monolayer of epitaxial graphene on SiC(0001) leads to the formation of quasi free standing small aggregates of clusters. Angle Resolved Photoemission Spectroscopy measurements reveal that these clusters preserve the linear dispersion of the graphene quasiparticles and surprisingly increase their Fermi velocity. They also strongly modify the band structure of graphene around the Van Hove singularities (VHs) by a strong extension without charge transfer. This result gives a new insight on the role of the intercalant in the renormalization of the bare electronic band structure of graphene usually observed in Graphite and Graphene Intercalation Compounds.