Structural and electronic properties of heterolayered gold, graphene and alkanethiol superlattices

In this study, common superlattices formed by rotational angle of graphene on Au(111) surface were determined for the first time using standard and dispersive corrected density functional theory (DFT) calculations. The morphological and electronic properties of these Au(111)/Graphene common supercells were studied with the inclusion of long-ranged weak interactions. In these structures, the effect of the positions of the carbon atoms of graphene with respect to the surface gold atoms, on the electronic properties is discussed. It has been determined by theoretical calculations that the Dirac cones of graphene are essentially not disturbed by weak electronic interactions between the gold surface and the graphene layer, and that the energy band structure keeps its linear behavior in the vicinity of the Dirac point. In addition, it was shown that the Fermi energy of gold-supported graphene shifted down relative to the Dirac point and was p-type doped. Alkanethiol molecules up to ten carbon chains were taken into consideration with isolated, striped phase and standing up phase self-assembled monolayer (SAM) formations, with physisorption and chemisorption modes, in Au(111)/Graphene/Alkanethiol and Au(111)/Alkanethiol/Graphene heterolayered common supercell compositions. Morphological and electronic properties of these three-component structures depending on the molecular density were revealed by DFT calculations including the van der Waals interactions. The results were discussed in comparison with Au(111)/Alkanethiol and Graphene/Alkanethiol bilayer systems. The effect of molecule-molecule interactions in SAM structures on the bonding stability of alkanethiol films on surfaces was investigated. Different possible variations of gold and graphene common supercells and properties of low and dense phase formations of alkanethiols in these systems were presented systematically.