Antiferroelectrics are among the most promising materials for applications as high energy storage capacitors [1,2]. Yet, the number of known antiferroelectrics is relatively small. Moreover, several experiments point at a polar behaviour in the prototypical antiferroelectric oxide, lead zirconate. In this work we use atomistic simulations to (1) predict new types of antiferroelectrics in oxide superlattices and (2) to study the possibility that PbZrO₃ not be antiferroelectric at ambient conditions.

First, we explore the design of artificial antiferroelectrics using PbTiO₃/SrTiO₃ superlattices [3]. When surrounding ferroelectric PbTiO₃ by dielectric SrTiO₃ layers, a competition between the polar distortion and the depolarizing field arises, often resulting in a rupture of PbTiO₃ into domains with opposite polarization. Such system can be considered antipolar (Fig. 1a), and can switch into a polar state under an electric field (Figs. 1b, c). We study the antiferroelectric-like response of such superlattices by means of second-principles calculations [4,5], and optimise their energy density and efficiency.

Second, we study a simple ferrielectric phase of PbZrO₃ (Fig. 2) that first principles calculations predict to be more stable than the commonly accepted antiferroelectric ground state [6]. We discuss the implications of our discovery, how it can be reconciled with the experimental observations and how the ferrielectric phase could be obtained in practice.

[1] K.M. Rabe, Antiferroelectricity in oxides: a reexamination in Functional Metal Oxides, Ch. 7, 221–244 (Wiley, 2013).
[2] Z. Liu, T. Lu, J. Ye, G. Wang, X. Dong, R. Withers, and Y. Liu, Antiferroelectrics for energy storage applications: a review. Advanced Materials Technologies 3, 1800111 (2018).
[3] H. Aramberri, N. S. Fedorova, J. Íñiguez, Ferroelectric/paraelectric superlattices for energy storage, Science Advances (in press), (2022).
[4] J. C. Wojdeł, P. Hermet, M. P. Ljungberg, P. Ghosez and J. Íñiguez, First-principles model potentials for lattice-dynamical studies: general methodology and example of application to ferroic perovskite oxides. Journal of Physics: Condensed Matter 25, 305401 (2013).
[5] P. García-Fernández, J. C. Wojdeł, J. Íñiguez and J. Junquera, Second-principles method for materials simulations including electron and lattice degrees of freedom. Physical Review B 93, 195137 (2016).
[6] H. Aramberri, C. Cazorla, M. Stengel, J. Íñiguez, On the possibility that PbZrO₃ not be antiferroelectric, npj Computational Materials 7, 196 (2021).