Two Distinct Phases of Bilayer Graphene Films on Ru(0001)

Marco Papagno , Daniela Pacile , Dinesh Topwal , Paolo Moras , Polina Makarovna Sheverdyaeva , Fabian Donat Natterer , Anne Lehnert , Stefano Rusponi , Quentin Dubout , Fabian Calleja , Emmanouil Frantzeskakis , Stéphane Pons (1) , Jun Fujii , Ivana Vobornik , Marco Grioni (2) , Carlo Carbone , Harald Brune

1 INSP - Institut des Nanosciences de Paris
2 EPFL - Ecole Polytechnique Fédérale de Lausanne

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 AS stacking with respect to the first graphene layer and displays weak vertical interaction and electron doping. The long-range ordered moire 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.

Mots clés: multilayer graphene; Ru; stacking sequence; photoemission; STM

Domaines: Matière Condensée [cond-mat]

Marco Papagno, Daniela Pacile, Dinesh Topwal, Paolo Moras, Polina Makarovna Sheverdyaeva, et al.. Two Distinct Phases of Bilayer Graphene Films on Ru(0001). ACS Nano, 2012, 6 (10), pp.9299-9304. ⟨10.1021/nn303821w⟩. ⟨hal-01233585⟩