title: Graphite, graphene on SiC, and graphene nanoribbons: Calculated images with a numerical FM-AFM.
abstract: BACKGROUND
  Characterization at the atomic scale is becoming an achievable task for FM-AFM users equipped, for example, with a qPlus sensor. Nevertheless, calculations are necessary to fully interpret experimental images in some specific cases. In this context, we developed a numerical AFM (n-AFM) able to be used in different modes and under different usage conditions.
  
  
  RESULTS
  Here, we tackled FM-AFM image calculations of three types of graphitic structures, namely a graphite surface, a graphene sheet on a silicon carbide substrate with a Si-terminated surface, and finally, a graphene nanoribbon. We compared static structures, meaning that all the tip and sample atoms are kept frozen in their equilibrium position, with dynamic systems, obtained with a molecular dynamics module allowing all the atoms to move freely during the probe oscillations.
  
  
  CONCLUSIONS
  We found a very good agreement with experimental graphite and graphene images. The imaging process for the deposited nanoribbon demonstrates the stability of our n-AFM to image a non-perfectly planar substrate exhibiting a geometrical step as well as a material step.
authors.affiliation: CEMES-CNRS, Centre d'élaboration des matériaux et d'études structurales, 29 rue Jeanne-Marvig, BP 94347, F-31055 Toulouse Cedex 4, France.
authors.forename: Fabien
authors.initials: F
authors.lastname: Castanié
authors.forename: Laurent
authors.initials: L
authors.lastname: Nony
authors.forename: Sébastien
authors.initials: S
authors.lastname: Gauthier
authors.forename: Xavier
authors.initials: X
authors.lastname: Bouju