The nature of ferroelectricity under pressure

Advances in first-principles computational approaches have, over the past fifteen years, made possible the investigation of physical properties of ferroelectric systems. In particular, such approaches have led to a microscopic understanding of the occurrence of ferroelectricity in perovskite oxides at ambient pressure. In this article, we report ab initio studies on the effect of hydrostatic pressure on the ferroelectricity in perovskites and related materials. We found that, unlike common belief, these materials exhibit ferroelectricity at high enough pressure. We also explain, in detail the ( unusual) nature of this ferroelectricity.