Two distinct phases of bilayer graphene films on Ru(0001)

ACS Nano. 2012 Oct 23;6(10):9299-304. doi: 10.1021/nn303821w. Epub 2012 Oct 5.

Abstract

By combining angle-resolved photoemission spectroscopy and scanning tunneling microscopy we reveal the structural and electronic properties of multilayer graphene on Ru(0001). We prove that large ethylene exposure allows the synthesis of two distinct phases of bilayer graphene with different properties. The first phase has Bernal AB stacking with respect to the first graphene layer and displays weak vertical interaction and electron doping. The long-range ordered moiré pattern modulates the crystal potential and induces replicas of the Dirac cone and minigaps. The second phase has an AA stacking sequence with respect to the first layer and displays weak structural and electronic modulation and p-doping. The linearly dispersing Dirac state reveals the nearly freestanding character of this novel second-layer phase.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Crystallization / methods*
  • Graphite / chemistry*
  • Macromolecular Substances / chemistry
  • Materials Testing
  • Membranes, Artificial*
  • Molecular Conformation
  • Nanostructures / chemistry*
  • Nanostructures / ultrastructure*
  • Phase Transition
  • Rubidium / chemistry*
  • Surface Properties

Substances

  • Macromolecular Substances
  • Membranes, Artificial
  • Graphite
  • Rubidium