Skip to Main content Skip to Navigation
Journal articles

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

Abstract : Earlier studies of C 60 adsorption on Au(111) reported many interesting and complex features. We have performed coordinated low-energy electron diffraction, scanning tunneling microscopy (STM), and density functional theory studies to elucidate some of the details of the monolayer commensurate (2Ý3 × 2Ý3)R30° phase. We have identified the adsorption geometries of the two states that image as dim and bright in STM. These consist of a C 60 molecule with a hexagon side down in a vacancy (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. A, 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)-(2Ý3 × 2Ý3)R30°-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.
Complete list of metadata

Cited literature [31 references]  Display  Hide  Download

https://hal.inria.fr/hal-01075806
Contributor : Emilie Gaudry <>
Submitted on : Monday, November 3, 2014 - 11:26:20 AM
Last modification on : Friday, February 26, 2021 - 12:38:02 PM
Long-term archiving on: : Friday, April 14, 2017 - 1:04:50 PM

File

PhysRevB.89.245428.pdf
Publisher files allowed on an open archive

Identifiers

Citation

Heekeun Shin, A Schwarze, Renee Diehl, Katariina Pussi, Arthur Colombier, et al.. Structure and dynamics of C 60 molecules on Au(111). Physical Review B: Condensed Matter and Materials Physics (1998-2015), American Physical Society, 2014, 89, 245428 (11 p.). ⟨10.1103/PhysRevB.89.245428⟩. ⟨hal-01075806⟩

Share

Metrics

Record views

423

Files downloads

611