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Structure and dynamics of C-60 molecules on Au(111)

TitleStructure and dynamics of C-60 molecules on Au(111)
Publication TypeJournal Article
Year of Publication2014
AuthorsShin, H, Schwarze, A, Diehl, RD, Pussi, K, Colombier, A, Gaudry, E, Ledieu, J, McGuirk, GM, Loli, LNS, Fournee, V, Wang, LL, Schull, G, Berndt, R
JournalPhysical Review B
Volume89
Pagination245428
Date Published06
Type of ArticleArticle
ISBN Number1098-0121
Accession NumberWOS:000340658000004
Keywordsag(111) surfaces, cu(111), films, fullerenes, ground-state, growth, metal-surfaces, reconstruction, solid c-60
Abstract

hex-vac) and a C-60 molecule with a carbon-carbon 6: 6 bond down on a top site (6:6-top), respectively. We have studied the detailed geometries of these states and find that there is little distortion of the C-60 molecules, but there is a rearrangement of the substrate near the C-60 molecules. The two types of molecules differ in height, by about 0.7 angstrom, which accounts for most of the difference in their contrast in the STM images. The monolayer displays dynamical behavior, in which the molecules flip from bright to dim, and vice versa. We interpret this flipping as the result of the diffusion of vacancies in the surface layers of the substrate. Our measurements of the dynamics of this flipping from one state to the other indicate that the activation energy is 0.66 +/- 0.03 eV for flips that involve nearest-neighbor C-60 molecules, and 0.93 +/- 0.03 for more distant flips. Based on calculated activation energies for vacancies diffusing in Au, we interpret these to be a result of surface vacancy diffusion and bulk vacancy diffusion. These results are compared to the similar system of Ag(111)-(2 root 3 x 2 root 3) R30 degrees- C-60. In both systems, the formation of the commensurate C-60 monolayer produces a large number of vacancies in the top substrate layer that are highly mobile, effectively melting the interfacial metal layer at temperatures well below their normal melting temperatures.

DOI10.1103/PhysRevB.89.245428
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