Scanning tunneling microscopy and kinetic Monte Carlo investigation of   Cesium superlattices on Ag(111)
  Cesium adsorption structures on Ag(111) were characterized in a low-temperature scanning tunneling microscopy experiment. At low coverages, atomic resolution of individual Cs atoms is occasionally suppressed in regions of an otherwise hexagonally ordered adsorbate film on terraces. Close to step edges Cs atoms appear as elongated protrusions along the step edge direction. At higher coverages, Cs superstructures with atomically resolved hexagonal lattices are observed. Kinetic Monte Carlo simulations model the observed adsorbate structures on a qualitative level. 
M. Ziegler, J. Kroeger, R. Berndt, A. Filinov, M. Bonitz