ELUCIDATING THE EQUILIBRIUM STATE OF C60 MOLECULES ON Ag(111)
Open Access
Author:
Su, Stephanie Yiin-ling
Area of Honors:
Physics
Degree:
Bachelor of Science
Document Type:
Thesis
Thesis Supervisors:
Renee Denise Diehl, Thesis Supervisor Dr. Richard Wallace Robinett, Thesis Honors Advisor
Keywords:
C60 Fullerene Flipping Ag(111) hops bright dim LEED DFT STM hex top
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√3 × 2√3)R30o phase of C60 on Ag(111), which consist of a mixture of two different states/orientations. The structure analysis identifies the orientation of the two types of molecules as – C60 sitting on a vacancy of Ag(111) substrate with hexagon face down and C60 sitting on the top site of Ag(111) surface with its C-C bond down. The molecules flip between two states at a temperature dependent rate. The dynamic of flipping involves the diffusion of the vacancies on Ag(111) surface, producing spatial and temporal correlation of the flipping events. By performing the study with STM, LEED, and DFT, we found the energy difference between two states to be 0.07 eV and the barrier to be 0.84 eV.
