... summarized as follows: for a surface potential of type, which describes, on the one hand, the atomic corrugation of the surface and, on the other, the decrease of the normal force for increasing tip–sample ... this wire was bent and electrochemically etched to serve as a probing tip. With a typical length of 12 mm and diameters of 0.25 and 0.5 mm, they obtained force constants of 150 and 2500 N/m, respectively, ... forceinstead of the normal force and so SFFM was born. They used an interferometric detection scheme tomeasure the displacement of a tungsten wire. As shown in Figure 6.5, the free end of this wire was...