title: Real-time imaging of K atoms on graphite: interactions and diffusion.
abstract: Scanning tunneling microscopy (STM) at liquid helium temperature is used to image potassium adsorbed on graphite at low coverage (≈0.02 monolayer). Single atoms appear as protrusions on STM topographs. A statistical analysis of the position of the atoms demonstrates repulsion between adsorbates, which is quantified by comparison with molecular dynamics simulations. This gives access to the dipole moment of a single adsorbate, found to be 10.5±1  D. Time-lapse imaging shows that long-range order is broken by thermally activated diffusion, with a 30 meV barrier to hopping between graphite lattice sites.
authors.affiliation: Department of Physics and Astronomy, University of British Columbia, Vancouver, British Columbia, V6T1Z4, Canada. renardj@phas.ubc.ca
authors.forename: J
authors.initials: J
authors.lastname: Renard
authors.forename: M B
authors.initials: MB
authors.lastname: Lundeberg
authors.forename: J A
authors.initials: JA
authors.lastname: Folk
authors.forename: Y
authors.initials: Y
authors.lastname: Pennec