Growth and properties of graphene on Hex-Au(001) reconstructed surface
Terasawa, Tomoo

Graphene, a two-dimensional material consisting of a honeycomb lattice of C atoms, has attracted much attention from basic physics to applications because of its extremely high carrier mobility and half-integer quantum Hall effect. Since a choice of substrate affects the properties of graphene, the synthesis and properties of graphene on various substrates have been the subject of surface science research. The interface between graphene and Au is expected in the field of spintronics because Au has a large atomic number and a large spin-orbit interaction. On the other hand, the atomic configuration in this interface is often unknown, and therefore, the angle-resolved photoemission spectroscopy (ARPES) experiments and density functional theory (DFT) calculations do not match each other for this interface. Here, we report the band structure of graphene on the Hex-Au(001) reconstructed surface using ARPES and DFT calculations. Since the solubility of C in Au is very low, graphene can be grown on Au surfaces by chemical vapor deposition (CVD). Hex-Au(001) reconstruction was kept even after the CVD growth of graphene. Therefore, the ARPES measurement was carried out for graphene on the well-known atomic configuration of Hex-Au(001). The ARPES intensity map shows the bandgap in the graphene pi band close to the Au 6sp band. The DFT calculated band structure shows the bandgap at the crossing point of the graphene pi and Au 6sp bands. We discuss that the bandgap originates from the hybridization between graphene and Au, similar to the case of graphene and Au interface on the SiC substrate. As the Rashba splitting of 100 meV was observed in the graphene and Au interface on the SiC substrate, we expect that the hybridization between graphene and Au is essential for the future applications of graphene for spintronic devices.