title: Atomically resolved orientational ordering of C60 molecules on epitaxial graphene on Cu(111).
abstract: A detailed understanding of interactions between molecules and graphene is one of the key issues for tailoring the properties of graphene-based molecular devices, because the electronic and structural properties of molecular layers on surfaces are determined by intermolecular and molecule-substrate interactions. Here, we present the atomically resolved experimental measurements of the self-assembled fullerene molecules on single-layer graphene on Cu(111). Fullerene molecules form a (4 × 4) superstructure on graphene/Cu(111), revealing only single molecular orientation. We can resolve the exact adsorption site and the configuration of fullerene by means of low-temperature scanning tunnelling microscopy (LT-STM) and density functional theory (DFT) calculations. The adsorption orientation can be explained in terms of the competition between intermolecular interactions and molecule-substrate interactions, where strong Coulomb interactions among the fullerenes determine the in-plane orientation of the fullerene. Our results provide important implications for developing carbon-based organic devices using a graphene template in the future.
authors.affiliation: School of Materials Science and Engineering, Center for Multidimensional Carbon Materials and Low Dimensional Carbon Materials Center, Ulsan National Institute of Science and Technology (UNIST), UNIST-gil 50, Ulsan 689-798, Republic of Korea. shinhj@unist.ac.kr.
authors.forename: Minbok
authors.initials: M
authors.lastname: Jung
authors.forename: Dongbin
authors.initials: D
authors.lastname: Shin
authors.forename: So-Dam
authors.initials: SD
authors.lastname: Sohn
authors.forename: Soon-Yong
authors.initials: SY
authors.lastname: Kwon
authors.forename: Noejung
authors.initials: N
authors.lastname: Park
authors.forename: Hyung-Joon
authors.initials: HJ
authors.lastname: Shin