Strong metal adatom–substrate interaction of Gd and Fe with graphene

• Published in: Journal of physics. Condensed matter 2011-02, Vol.23 (4), p.045005-7
• Main Authors: Hupalo, M, Binz, S, Tringides, M C
• Format: Article
• Language: English
• Subjects: Coarsening; Condensed matter; Condensed matter: structure, mechanical and thermal properties; Density; Doping; Exact sciences and technology; Graphene; Iron; Islands; Physics; Rare earth metals; Solid surfaces and solid-solid interfaces; Surface structure and topography; Surfaces and interfaces; thin films and whiskers (structure and nonelectronic properties)
• ISSN: 0953-8984; 1361-648X
• DOI: 10.1088/0953-8984/23/4/045005

Graphene is a unique 2D system of confined electrons with an unusual electronic structure of two inverted Dirac cones touching at a single point, with high electron mobility and promising microelectronics applications. The clean system has been studied extensively, but metal adsorption studies in controlled experiments have been limited; such experiments are important to grow uniform metallic films, metal contacts, carrier doping, etc. Two non-free-electron-like metals (rare earth Gd and transition metal Fe) were grown epitaxially on graphene as a function of temperature T and coverage θ. By measuring the nucleated island density and its variation with growth conditions, information about the metal-graphene interaction (terrace diffusion, detachment energy) is extracted. The nucleated island densities at room temperature (RT) are stable and do not coarsen, at least up to 400 °C, which shows an unusually strong metal-graphene bond; most likely it is a result of C atom rebonding from the pure graphene sp(2) C-C configuration to one of lower energy.