We investigate molecule-molecule, as well as molecule-substrate, interactions of phthalocyanine molecules deposited on graphene. In particular, we show how to tune the self-assembly of molecular lattices in two dimensions by intercalation of transition metals between graphene and Ir(111): modifying the surface potential of the graphene layer via intercalation leads to the formation of square, honeycomb, or Kagome lattices. Finally, we demonstrate that such surface induced molecular lattices are stable even at room temperature.

The design of nanoscale organic-metal hybrids with tunable magnetic properties as well as the realization of controlled magnetic coupling between them open gateways for novel molecular spintronic devices. Progress in this direction requires a combination of a clever choice of organic and thin-film materials, advanced magnetic characterization techniques with a spatial resolution down to the atomic length scale, and a thorough understanding of magnetic properties based on first-principles calculations. Here, we make use of carbon-based systems of various nanoscale size, such as single coronene molecules and islands of graphene, deposited on a skyrmion lattice of a single atomic layer of iron on an iridium substrate, in order to tune the magnetic characteristics (for example, magnetic moments, magnetic anisotropies and coercive field strengths) of the organic-metal hybrids. Moreover, we demonstrate long-range magnetic coupling between individual organic-metal hybrids via the chiral magnetic skyrmion lattice, thereby offering viable routes towards spin information transmission between magnetically stable states in nanoscale dimensions.

Making use of the inherent surface anisotropy of different high index surface planes vicinal to the low index Au(111) orientation, one-dimensional polymers have been synthesized following established procedures from two different precursor molecules. The successful polymerization of both 4,4″-dibromo-p-terphenyl and 5,5′-dibromo-salophenato-Co(II) precursors into poly(p-phenylene) and poly-[salophenato-Co(II)], respectively, has been confirmed by scanning tunneling microscopy and low energy electron diffraction. Angle-resolved photoemission spectroscopy data reveal a highly dispersive band in the case of poly(p-phenylene) while no significant dispersion is resolved for poly[salophenato-Co(II)]. On the basis of density functional theory calculations, we explain this observation as a result of a high conjugation along the aromatic phenyl groups in poly(p-phenylene) that is absent in the case of poly[salophenato-Co(II)], where intramolecular conjugation is interrupted in the salophenato-Co(II) unit. Furthermore, we make use of multicenter and delocalization indexes to characterize the electron mobility (corresponding to a high band dispersion) along different paths associated with individual molecular orbitals.