Elucidating the dynamical equilibrium of C-60 molecules on Ag(111)

TitleElucidating the dynamical equilibrium of C-60 molecules on Ag(111)
Publication TypeJournal Article
Year of Publication2012
AuthorsPussi K, Li HI, Shin H, Loli LNS, Shukla AK, Ledieu J, Fournee V, Wang LL, Su SY, Marino KE, Snyder MV, Diehl RD
Journal TitlePhysical Review B
Volume86
Pages205406
Date Published11
Type of ArticleArticle
ISBN Number1098-0121
Accession NumberWOS:000310684900016
Keywordsau(111), surface
Abstract

We have used scanning tunneling microscopy (STM), low-energy electron diffraction (LEED), and density functional theory (DFT) to elucidate the structure and thermodynamics of the (2 root 3 x 2 root 3) R30 degrees phase of C-60 on Ag(111), which consists of a mixture of molecules in two different site/orientation states. The structure analysis identifies the two types of molecules as (1) sitting on a vacancy with a hexagon face down and (2) sitting on a top site with a C-C bond down. The molecules flip between the two states at a temperature-dependent rate. We show using a thermodynamic analysis that the two states differ by 0.07 eV and are separated by an energy barrier of 0.84 eV. Their dynamical equilibrium involves the diffusion of surface vacancies between C60 molecules, producing spatially and temporally correlated flipping events.

URL<Go to ISI>://WOS:000310684900016
DOI10.1103/PhysRevB.86.205406
Alternate JournalPhys. Rev. B