3. General principle of contact-mode atomic force microscopy

Atomic force microscopy belongs to the large family of near-field microscopies, which share the characteristic of being based on the same principle: bringing a nanometer-sized probe as close as possible to the surface to be studied. The probe is placed on the surface in the case of the so-called "contact mode", and is held at an average distance of a few nanometers (up to a few tens of nanometers) in the case of the so-called "non-contact" or "intermittent contact" modes. It is beyond the scope of this article to describe atomic force microscopy in detail, so we'll confine ourselves to the basics, particularly those concerning the contact mode on which ferroelectric polarization mapping is based. More information can be found in the article