Survey of structural and electronic properties of C₆₀ on close-packed metal surfaces

The adsorption of buckminsterfullerene (C₆₀) on metal surfaces has been investigated extensively for its unique geometric and electronic properties. The two-dimensional systems formed on surfaces allow studying in detail the interplay between bonding and electronic structures. Recent studies reveal that C₆₀ adsorption induces reconstruction of even the less-reactive close-packed metal surfaces. First-principles computations enable access to this important issue by providing not only detailed atomic structure but also electronic properties of the substrate-adsorbate interaction, which can be compared with various experimental techniques to determine and understand the interface structures. This review discusses in detail the ordered phases of C₆₀ monolayers on metal surfaces and the surface reconstruction induced by C₆₀ adsorption, with an emphasis on the different types of reconstruction resulting on close-packed metal surfaces. We show that the symmetry matching between C₆₀ molecules and metal surfaces determines the local adsorption configurations, while the size matching between C ₆₀ molecules and the metal surface lattice determines the supercell sizes and shapes; importantly and uniquely for C₆₀, the number of surface metal atoms within one supercell determines the different types of reconstruction that can occur. The atomic structure at the molecule-metal interface is of crucial importance for the monolayer's electronic and transport properties: these will also be discussed for the well-defined adsorption structures, especially from the perspective of tuning the electronic structure via C₆₀-metal interface reconstruction and via relative inter-C ₆₀ orientations.