A similar microscopy technique exists, where the tip does not make contact with the surface, but is instead kept within a nanometer from the surface. At that sc

A similar microscopy technique exists, where the tip does not make contact with the surface, but is instead kept within a nanometer from the surface. At that scale, due to effect I can't claim to understand (quantum tunneling) small amounts of current (~pA-nA) is flowing between the tip and surface. This makes it possible to image the surface at atomic scale by controlling the height of the tip while the tunneling current is kept constant: result is a depth map of atomic structure.