Formation of Moiré superstructure of epitaxial graphene on Pt(111): A molecular dynamic simulation investigation

The moiré superstructures formed in the graphene on Pt (111) surface have been studied employing classical molecular dynamics (CMD) simulation. We have shown that the 20 moiré superstructures, whose positions and periodicities are the same as the prediction of the geometric model proposed by Merino, can be obtained via the rotation of graphene. This observation demonstrates that molecular dynamics simulation is an effective method for searching for moiré superstructure formed in the graphene on transition metal surface. The characteristics of moiré superstructures, such as fluctuation of the graphene layer, C–C bond length and stress of carbon atoms, are investigated. For the superstructures with large periodicity, the graphene layer is fluctuant. In the region of the maximal height of the superstructure, there is a strong attraction between the graphene and Pt substrate, so that the carbon atoms are concave, and the C–C bonds are stretched by 0.0004 Å. In the region of the minimal height of the superstructure, the C–C bond lengths are the same as those in freestanding graphene. Additionally, a moiré superstructure with an ultra-long periodicity (L = 60.1 Å) is observed, and its formation mechanism is discussed. •Used CMD method to study the moiré structures of the graphene on Pt(111) surface.•Observed some structures with the same properties as that of Merino's model.•Investigated the graphene fluctuation, C–C bond length and the stress of C atoms.•Discussed the formation mechanism of the structure with ultra-long periodicity.