Highlights Surface Science Lab

Since its first isolation, graphene has attracted a staggering interest due to its outstanding properties, ranging from its electrical conductivity to its mechanical, optical and chemical properties. This unique two-dimensional material may be therefore exploited for a wealth of industrial applications in particular when supported on suitable solid surfaces. However, due to its interaction with the substrate, graphene exhibits distinct properties with respect to free-standing graphene. The interaction strength with the substrate directly affects the corrugation of the carbon film, thus resulting in different thermal stability and heat conductivity.
In this work we have investigated epitaxial graphene grown on Re(0001), which can be considered as a model strongly interacting system. Our innovative approach exploits the combined use of synchrotron based experimental techniques available at the SuperESCA and Nanospectroscopy and density functional theory calculations.  Our results show that the graphene layer is strongly corrugated, with nanometer scale periodic mounds and valleys.

However, in contrast with what observed on other metals, graphene on Re(0001) dissolves at high temperature, despite the intrinsic thermal stability of the carbon network. Noteworthy, we could locate the onset of C-C bond breaking in the strongly interacting regions of the graphene sheet, where C atoms are closer to the substrate. The mechanism of GR breaking involves the presence of C vacancies, which quickly migrate to the strongly interacting regions where subsequent C-C bond breakup takes place.

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Thermal Stability of Corrugated Epitaxial Graphene Grown on Re(0001);
E. Miniussi, M. Pozzo, A. Baraldi, E. Vesselli, R. R. Zhan, G. Comelli, T.O. Menteş¸ M.Á. Niño, A. Locatelli, S. Lizzit, and D. Alfe';
Phys. Rev. Lett. 106, 216101 (2011).