Modeling and control principle for ferroelectric. Antiferroelectric phase transition

Ferroelectricity and antiferroelectricity are of great importance not only in condensed matter physics but also in technological applications due to their electrical controllability and cross-coupling effects such as electromechanical and electrocaloric responses. We here develop a simple model system composed of spheroid-like particles with a permanent dipole, which may capture an essence of phase transitions between ferroelectric and antiferroelectric phases. With this model, we reveal that energetic frustration between the dipole-dipole interaction and interparticle steric interaction is a key to control ferroelectric-antiferroelectric phase transition accompanied by electromechanical coupling. We also show that the inverse electrocaloric effect can be induced as a consequence of the entropy difference between the ferroelectric and antiferroelectric phases. Thus, we reveal a simple physical principle behind the coupling between polarization ordering and structural phase transition responsible for large electromechanical effects. It may apply to organic and macromolecular systems. (author)