True atomic resolution under ambient conditions obtained by atomic force microscopy in the contact mode

) has been investigated by contact-mode atomic force microscopy (AFM) in air. Both the terraces and the monolayer step itself were reproducibly imaged at atomic resolution in the repulsive-force regime at forces between tip apex and sample of the order of 10-9 N. Several kinks were also imaged at atomic resolution. Details of the atomic registry of subsequent Se-Nb-Se sandwich layers as well as the arrangement of the individual atoms at the kink sites were resolved. The results are in perfect quantitative agreement with the lattice structure known from X-ray analysis and indicate that true atom-by-atom lateral resolution of microscopic defects is feasible by AFM in the contact mode and under ambient conditions.