Structure determinations of graphene and silicene on metal surfaces using total-reflection high-energy positron diffraction

We report on structure determinations of graphene and silicene on metal substrates using total-reflection high-energy positron diffraction (TRHEPD) technique. The magnitude of buckling in graphene (silicene) and the spacing between graphene and substrate are crucial to elucidate the origin of the electronic property of graphene adsorbed on a substrate. In this study, these structure parameters for graphene/Co(0001), graphene/Cu(111), and silicene/Ag(111) were determined with the aid of surface sensitivity of the TRHEPD. The experimental verification of these parameters will promote a better understanding of the properties of graphene and silicene. (author)