Dependence of critical thickness of particle-size for ferroelectricity in BaTiO3 by Ab initio calculations

Particle-size effects on the critical thickness of the ferroelectric properties of nanoscale BaTiO3 particles are investigated using a first-principles molecular orbital method and population analysis for the net charge and overlap population. A series of models composed of a Ba8Ti7O6 cluster and point charges surrounding the cluster are employed for calculations of the electronic structures of the BaTiO3 particles, with the size of the model defined by the size of the point charge array. Results of the calculations show that the critical thickness for the ferroelectric-to-paraelectric transition for nanoscale BaTiO3 particles decreases as the area of the base of the rectangular particles decreases. (author)