The AFM uses a sharp tip mounted on a flexible beam – akin to a tiny diving board – to measure the interaction between the tip and the atoms on a surface. In the present work, the flexible beam was actually a miniature quartz tuning fork of the type commonly found in clocks and wrist watches. When the tip is positioned close to an atom on the surface, the frequency of the tuning fork changes slightly. The frequency change can be analyzed to determine the force exerted on the atom.
