Topographic and electronic contrast of the graphene moiré on Ir(111) probed by scanning tunneling microscopy and non-contact atomic force microscopy

Abstract

Epitaxial graphene grown on transition metal surfaces typically exhibits a moiré pattern due to the lattice mismatch between graphene and the underlying metal surface. We use both scanning tunneling microscopy (STM) and atomic force microscopy (AFM) experiments to probe the electronic and topographic contrast of the graphene moiré on the Ir(111) surface. While STM topography is influenced by the local density of states close to the Fermi energy and the local tunneling barrier height, AFM is capable of yielding the 'true' surface topography once the background force arising from the van der Waals (vdW) interaction between the tip and the substrate is taken into account. We observe a moiré corrugation of 35$\pm$10 pm, where the graphene-Ir(111) distance is the smallest in the areas where the graphene honeycomb is atop the underlying iridium atoms and larger on the fcc or hcp threefold hollow sites.

revised version

References in corpus (5)

• Periodically rippled graphene: growth and spatially resolved electronic structure
• Two Dimensional Ir-Cluster Lattices on Moiré of Graphene with Ir(111)
• Dirac Cones and Minigaps for Graphene on Ir(111)
• Unit cell of graphene on Ru(0001): a 25 x 25 supercell with 1250 carbon atoms
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Cited by in corpus (4)

• Electronic structure, imaging contrast and chemical reactivity of graphene moiré on metals
• Angle-Dependent van Hove Singularities and Their Breakdown in Twisted Graphene Bilayers
• Topography of the graphene/Ir(111) moir{é} studied by surface x-ray diffraction
• Multilayer graphene, Moiré patterns, grain boundaries and defects identified by scanning tunneling microscopy on the m-plane, non-polar surface of SiC