Departure from the conical dispersion in epitaxial graphene

TL;DR

This study reveals deviations from the expected conical dispersion in epitaxial graphene's pi bands, indicating a possible intrinsic band gap and many-body interaction effects, which could enable band gap engineering.

Contribution

The paper provides experimental evidence of a band gap in epitaxial graphene and discusses its implications for band structure manipulation.

Findings

Deviations from conical dispersion near the Dirac point

Evidence supporting the opening of a band gap

Anomalous increase in scattering rate

Abstract

The pi bands of epitaxially grown graphene are studied by using high resolution angle resolved photoemission spectroscopy. Clear deviations from the conical dispersion expected for massless Dirac fermions and an anomalous increase of the scattering rate are observed in the vicinity of the Dirac point energy. Possible explanations for such anomalies are discussed in terms of many-body interactions and the opening of a gap. We present detailed experimental evidences in support of the gap scenario. This finding reveals a fundamental intrinsic property of epitaxial graphene and demonstrates the possibility of engineering the band gap in epitaxial graphene.