Computer-aided modeling of dielectric and ferroelectric properties

In this article the concept of charges fluctuating in double well potentials is used as a basis for a quantitative computer calculation of interactions between permanent dipoles. Numerical calculations are of advantage, because the dipole-dipole interaction energy can exceed the thermal energy. In this case nonlinearities can arise, which are difficult to treat analytically. Furthermore, a numerical recalculation of the Lorentz field resulting from induced dipoles has been carried out. Within the Lorentz calculation of the local field, two models are used in juxtaposed position: a discrete model, which takes account of dipoles inside a conceptual sphere, and a continuum model, which treats the dipoles outside this sphere as a continuum. Using both models the local field at the center dipole of the sphere is calculated. It is shown that several dielectric and ferroelectric properties can be calculated using very simple model assumptions.