Ferroelectric solids contain electric dipoles that are intrinsic to the atomic structure of the compound. For example in a cubic perovskite, the displacement of the body center cation in the unit cell produces a dipole in the structure. Dipole-dipole interaction between cells cause polarization alignment resulting in ferroelectric domains. Polarization discontinuities in the vicinity of surfaces and interfaces result in polarization bound charge that significantly affects materials properties.
Polarization induced band bending at the ferroelectric surfaces results in the domain-specific photochemical activity. The mechanism of this phenomenon is shown below:
Combined with the possibility to control local domain structure by AFM, this opens a wide range of possibilities for the controlled preparation of nanoscale structures.
This is an example of gold nanoparticles photochemically grown on BaTiO3 surface.