DYNAMIC SFM WITH TRUE ATOMIC-RESOLUTION ON ALKALI-HALIDE SURFACES

Large-amplitude dynamic force microscopy is used to study alkali halid e surfaces. The {001} cleavage faces of NaF, RbBr, LiF, KI and NaCl co uld be atomically resolved with excellent stability. In all cases the observed lattice periods correspond to the bulk lattice of equally cha rged ions. The resonance frequency shift and the atomic corrugation am plitude tend to increase after successive tip crashes. This behaviour is explained by analogy with scanning tunnelling microscopy. In additi on, the mean atomic corrugation is found to be comparable to the diffe rence between the anion and cation ionic radii.