Topography of the graphene/Ir(111) moiré studied by surface x-ray diffraction

Fabien Jean (1) , Tao Zhou (2) , Nils Blanc (3) , Roberto Felici (4) , Johann Coraux (1) , Gilles Renaud (2)

1 NEEL - Quan2m - Interactions modulables dans des états quantiques 2D
2 INAC - Institut Nanosciences et Cryogénie
3 NEEL - CRG - CRG & Grands instruments
4 ESRF - European Synchrotron Radiation Facility

The structure of a graphene monolayer on Ir(111) has been investigated {\it in situ} in the growth chamber by surface x-ray diffraction including the specular rod, which allows disentangling the effect of the sample roughness from that of the nanorippling of graphene and iridium along the moiré-like pattern between graphene and Ir(111). Accordingly we are able to provide precise estimates of the undulation associated with this nanorippling, which is small in this weakly interacting graphene/metal system and thus proved difficult to assess in the past. The nanoripplings of graphene and iridium are found in phase, i.e. the in-plane position of their height maxima coincide, but the amplitude of the height modulation is much larger for graphene (\(0.379 \pm 0.044\) \AA) than, {\it e.g.}, for the topmost Ir layer (\(0.017 \pm 0.002\) \AA). The average graphene-Ir distance is found to be \(3.38 \pm 0.04\) \AA.

Domaines: Science des matériaux [cond-mat.mtrl-sci]

Fabien Jean, Tao Zhou, Nils Blanc, Roberto Felici, Johann Coraux, et al.. Topography of the graphene/Ir(111) moiré studied by surface x-ray diffraction. Physical Review B: Condensed Matter and Materials Physics (1998-2015), 2015, 91 (24), pp.245424. ⟨10.1103/PhysRevB.91.245424⟩. ⟨hal-01167574⟩