Raw images showing the friction signal in the left-to-right sliding direction. Upper row: 4-layer graphene; lower row: bulk graphite; right column: Low-pass filtered images of the friction measurements showing the periodicity of the lattice. Black dots represent the periodic sites of the friction force signal. The scale bars correspond to 0.5 nm.
RHK SPM 100
Q. Li and R.W. Carpick, University of Pennsylvania
Science 328, 76 (2010) DOI: 10.1126/science.1184167