Formation of Moire superstructure of epitaxial graphene on Pt(111): A molecular dynamic simulation investigation
B Sun and WZ Ouyang and JB Gu and CJ Wang and JJ Wang and LW Mi, MATERIALS CHEMISTRY AND PHYSICS, 253, 123126 (2020).
The moire superstructures formed in the graphene on Pt (111) surface have been studied employing classical molecular dynamics (CMD) simulation. We have shown that the 20 moire 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 moire superstructure formed in the graphene on transition metal surface. The characteristics of moire 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 angstrom. 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 moire superstructure with an ultra-long periodicity (L = 60.1 angstrom) is observed, and its formation mechanism is discussed.
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