Angle dependence of the interaction distance in the shear force technique.

We study the interaction distance in the lateral force detection, using a standard quartz tuning fork as a force transducer. That is the distance at which the interaction sample-probe starts to be detected. We study in particular the dependence on the approaching angle. For angles smaller than 0.366 radians, we found an exponential behavior of the interaction distance as a function of the approaching angle. We show an equation that adjusts well with the experimental data, and discuss the possible phenomena.