Michael Ellner, Niko Pavliček, et al.
Nano Letters
An atomic force microscope capable of measuring, simultaneously yet separately, lateral ("frictional") and normal forces is described. A direction-dependent feature, absent in topological images, is found when scanning stepped surfaces of NaCl (001) in ultrahigh vacuum. A simple model is presented to account for this observation.
Michael Ellner, Niko Pavliček, et al.
Nano Letters
Karl-Heinz Rieder, Gerhard Meyer, et al.
Philos. Trans. R. Soc. A
Gerhard Meyer, Nabil M. Amer
Applied Physics Letters
Peter Liljeroth, Jascha Repp, et al.
Science