1.    Parabolic or spherical probe.

The model applies to probes with a spherical tip at small tip-sample separations . The same result is obtained generally for the parabolic tip. , , : .

(1)

In AFM measurements with silicon probe and sample at

2.    Conical probe.

The model applies in case when tip curvature radius can be neglected as compared to tip-sample separation (). , , : .

(2)

In AFM measurements with silicon probe and sample at

3.    Pyramidal probe.

The model applies in case when tip curvature radius can be neglected as compared to tip-sample separation (). , , : .

(3)

In AFM measurements with silicon probe and sample at

4.    Conical probe with a rounded tip.

The model is a generalization of (1) and (2) at arbitrary ratio between and .

(4)

where . At (semispherical probe) formula (4) transforms into formula (1) while at (conical probe) – into formula (2).

In AFM measurements with silicon probe and sample at , , : .