Place: Online event
Jorge Iñiguez, Luxembourg Institute of Science and Technology, Esch-sur-Alzette, Luxembourg
Antiferroelectric materials (e.g., perovskite oxide PbZrO3) are characterized by a strongly non-linear polarization response to an applied electric field, featuring a field-induced phase transition to a polar state. This peculiar behavior makes them interesting for a variety of applications, e.g., to construct high energy-density pulsed-power capacitors. However, the scarcity of antiferroelectric materials hampers progress and makes it difficult to optimize performance. In this talk, I will discuss our recent theoretical efforts to identify compounds that present antiferroelectric behavior, with the primary goal of optimizing their energy-storage performance. I will present two research lines. First, I will show how a high-throughput first-principles investigation of perovskite oxides (initially aimed at finding dominant antipolar lattice instabilities in this family) led us to predict that long-known pyroxene-like compounds like KVO3 are antiferroelectric. Further, we noticed that the (antipolar) structural features enabling this behavior are also present in other all-important mineral families, suggesting that they too are candidates to display antiferroelectric properties . Second, I will show how we can “electrostatic engineer” regular ferroelectric compounds so that they behave as antiferroelectrics. More precisely, our second-principles simulations of PbTiO3/SrTiO3 superlattices – known to display short-period multidomain structures that can be viewed as antipolar arrangements  – predict an antiferroelectric-like response to an electric field . Further, we show that the behavior of these superlattices can be optimized through various design parameters (e.g., layer thickness, epitaxial strain) to reach energy densities and efficiencies of the same order as the best-performing antiferroelectric compounds (e.g., exceeding 100 J/cm3 with 100% efficiency for a field of 3.5 MV/cm).
 Antiferroelectricity in a family of pyroxene-like oxides with rich polymorphism, H. Aramberri and J. Íñiguez, Communications Materials 1, 52 (2020).
 Observation of polar vortices in oxide superlattices, A.K. Yadav et al., Nature 530, 198 (2016).
 H. Aramberri, N. Fedorova and J. Íñiguez, in preparation (2021).