For the purpose of recovering the intriguing electronic properties of freestanding graphene at a solid surface, graphene self-organized on a Au monolayer on Ni(111) is prepared and characterized by scanning tunneling microscopy. Angle-resolved photoemission reveals a gapless linear $\pi$-band dispersion near $\overline{K}$ as a fingerprint of strictly monolayer graphene and a Dirac crossing energy equal to the Fermi energy ($E_F$) within 25 meV meaning charge neutrality. Spin resolution shows a Rashba effect on the $\pi$ states with a large ($\sim 13\mathrm{meV}$) spin-orbit splitting up to $E_F$ which is independent of $\mathbf{k}$.

Graphene in spintronics is predominantly considered for spin current leads of high performance due to weak intrinsic spin–orbit coupling of the graphene π electrons. Externally induced large spin–orbit coupling opens the possibility of using graphene in active elements of spintronic devices such as the Das-Datta spin field-effect transistor. Here we show that Au intercalation at the graphene–Ni interface creates a giant spin–orbit splitting (~100 meV) of the graphene Dirac cone up to the Fermi energy. Photoelectron spectroscopy reveals the hybridization with Au 5d states as the source for this giant splitting. An ab initio model of the system shows a Rashba-split spectrum around the Dirac point of graphene. A sharp graphene–Au interface at the equilibrium distance accounts for only ~10 meV spin–orbit splitting and enhancement is due to the Au atoms in the hollow position that get closer to graphene and do not break the sublattice symmetry.

Angle-resolved photoemission and scanning tunneling microscopy have been applied to study the intercalation of copper underneath a monolayer of graphite (MG) on Ni(111). The room-temperature deposition of copper on MG/Ni(111) in the coverage range 4–12 Å leads to the growth of Cu islands on the MG. Annealing of the “as-deposited” system at a temperature of 400 °C results in the intercalation of all Cu atoms underneath the MG. The intercalation of Cu is followed by a shift of the graphite-derived valence bands toward energies that are characteristic of pristine graphite. This observation is understood in terms of a weakening of chemical bonding between the MG and the substrate in the MG/Cu/Ni(111) system.

Quasi-two-dimensional intercalationlike systems, synthesized by surface intercalation of gold atoms underneath a monolayer of graphite formed on Ni(111), have been investigated by angle-resolved photoemission spectroscopy (PES) and high-resolution electron-energy-loss spectroscopy (HREELS). Modifications of both electronic structure and vibrational properties due to the presence of the intercalated Au monolayer between the graphite monolayer and Ni(111) are reported. The surface intercalation of the gold atoms underneath the graphite monolayer leads to a “stiffening” of the graphite-derived phonon modes and to an energetic shift of the graphite-derived π, σ electronic states in the valence band toward lower binding energies. The observed changes of the PE and HREEL spectra are explained by the saturation of the active $\mathrm{Ni}\mathrm{}\left(d\right)\mathrm{}$ bonds by the intercalated gold atoms and by the weakening of the interaction between graphite monolayer and substrate, due to the blockage of the graphite $\mathrm{C}\left(\pi \right)-\mathrm{Ni}\mathrm{}\left(d\right)\mathrm{}$ hybrid bonds.

Graphene is considered a candidate material for spintronics. Recently, graphene grown on Ni(111) has been reported to show a Rashba effect which depends on the magnetization. By spin- and angle-resolved photoelectron spectroscopy, we investigate the preconditions for such an effect for graphene on Ni as well as on Co which has a $\sim 3\times$ larger $3d$ magnetic moment: (i) spin polarization or (ii) exchange splitting of graphene $\pi$ states in normal emission geometry, and (iii) Rashba-type spin-orbit splitting off normal. As none of these are found to be of considerable size, the reported effect is neither Rashba-type, nor due to the spin-orbit coupling, nor involving the electron spin.