Dirac Cones and Minigaps for Graphene on Ir(111)

TL;DR

This study uses angle-resolved photoelectron spectroscopy to analyze high-quality epitaxial graphene on Ir(111), revealing Dirac cones, superperiodic potentials, and minigaps caused by lattice interactions.

Contribution

It provides detailed experimental evidence of Dirac cone replicas and minigaps in graphene on Ir(111), highlighting the effects of moire superlattices.

Findings

Dirac cone with the Dirac point slightly above Fermi level

Observation of Dirac cone replicas due to moire pattern

Detection of minigaps in the band structure

Abstract

Epitaxial graphene on Ir(111) prepared in excellent structural quality is investigated by angle-resolved photoelectron spectroscopy. It clearly displays a Dirac cone with the Dirac point shifted only slightly above the Fermi level. The moire resulting from the overlaid graphene and Ir(111) surface lattices imposes a superperiodic potential giving rise to Dirac cone replicas and the opening of minigaps in the band structure.