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Graphene on Ru(0001) Moiré Corrugation Studied by Scanning Tunneling Microscopy on Au/Graphene/Ru(0001) Heterostructures
journal contribution
posted on 2016-02-18, 16:32 authored by R. Cortés, D. P. Acharya, C. V. Ciobanu, E. Sutter, P. SutterTwo-dimensional
Au islands of different thicknesses grown on graphene/Ru(0001)
were used to study the corrugation of the moiré structure of
graphene/Ru(0001) and discriminate between its mainly structural or
electronic character. A comparison of the apparent corrugation measured
by scanning tunneling microscopy (STM) for different Au thicknesses
with results of elasticity theory equations applied to a gold film
over a corrugated substrate shows that the corrugation observed for
the graphene/Ru(0001) moiré is of structural nature rather
than electronic. STM showed a large value for the corrugation of the
first Au monolayer on graphene/Ru(0001), 1.7 Å; using density
functional theory calculations, we explain this large corrugation
of the Au monolayer as the result of a strong (weak) binding of the
Au layer at the valley (hill) regions of the graphene/Ru(0001) moiré
structure and infer an actual corrugation of the graphene/Ru(0001)
moiré structure of ∼1.2 Å from the measured corrugation
of the Au monolayer.