Regensburg 2013 – scientific programme
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TT: Fachverband Tiefe Temperaturen
TT 71: Graphene - Preparation and Characterization 2 (jointly with DS, HL, MA, and O)
TT 71.8: Talk
Friday, March 15, 2013, 12:15–12:30, H17
Role of substrate-molecular interactions in arrangement and collective motion of fullerene islands on graphene — •Martin Svec1, Pablo Merino2, Yannick Dappe3, Cesar Gonzalez1, Enrique Abad4, Pavel Jelinek1, and Jose-Angel Martin-Gago5 — 1Institute of Physics, ASCR, Prague, CZ — 2CAB INTA-CSIC, Madrid, ES — 3CEA, IRAMIS, SPCSI, FR — 4UAM, Madrid, ES — 5ICMM-CSIC, Madrid, ES
Fullerenes interacting with graphene are a model system, that should be entirely driven by van der Waals (vdW) interactions. We concentrate on the interactions occurring between fullerenes and the single-layer graphene grown on SiC(0001) [1]. By using a VT-STM at 40K, regular islands of fullerenes were found. The particular orientation of the fullerenes in the islands, which occupy 4x4 graphene unit cells each, is critically evaluated by a comparison of STM measurements to extensive STM simulations with realistic fullerene-terminated tips. The determined orientation of fullerenes is independently confirmed by complex theoretical calculations of several adsorption configurations, taking into account the vdW interaction between the constituents of this system. Furthermore, islands of fullerenes were found collectively moving on the graphene. Surprisingly, according to the theory, the cohesion among the fullerenes is weaker than adhesion to the surface. Nevertheless, cohesion is a decisive factor in the collective motion, thanks to a low diffusion barrier of fullerenes on graphene.
[1] M. Švec et al., Phys. Rev. B 86 121407(R)(2012)