Extended Data Fig. 3: Visualization of the condensation transition using AFM.

a–c, Images of a graphite capillary with N = 3 at RH of 55%, 70% and 95% (a, b and c, respectively). The upper part of each image shows sagging of the top graphite crystal (H ≈ 80 nm) into the 2D channel. The lower part shows the area immediately outside the channel, which is not covered by the top graphite. The black dotted lines mark a border between the two regions (edge of the top crystal). The colour scales for the lower and upper parts of the AFM images are given by the green and black curves, respectively. The profiles are averaged over ∼100 nm along the y direction, and the curves in the upper parts of all the panels are provided on the same scale given by the black arrows in panel a. A small number of horizontal scanning lines (x direction) around the black-dot dividing lines were removed for clarity because they contained numerous instabilities caused by the AFM tip moving along the edge of the top crystal and jum** up and down. Such instabilities are typical for AFM scanning close to edges.