Local fields, polarization, and electrode effects in systems of induced dipoles

As is known, the Lorentz formula can be used to calculate the local electri c field at atoms on cubic lattice sites and to calculate the electrical pol arization of the lattice. While in this case the lattice consists of only o ne species of atoms, the present article describes a numerical method to ca lculate the local field and the polarization of materials with two species of atoms in a lattice of finite size. The atoms are different with respect to their polarizabilities. To calculate the local fields in a finite system of dipoles embedded between electrodes, the method of images is used. In a ddition, the effect of the electrodes with their image dipoles on the polar ization is investigated for the case of identical atoms, i.e., atoms with t he same polarizability: an air gap between the dipole lattice and one of th e two electrodes is assumed and varied, and the local fields and induced mo ments on the lattice sites are calculated.