By analogy to antiferromagnets, antiferroelectrics are defined by having two antiparallel dipolar sublattices. Upon application of a sufficiently large electric field, the dipoles in these sub-latticesare re-oriented parallel to each other, resulting in a voltage-induced ferroelectric-like state. Thisfield-induced transition is useful, with applications including energy storage, photovoltaics, and solid-state cooling via a “giant” negative electrocaloric effect, whereby the antiferroelectric cools down as a voltage is applied to it. In addition, and on a more fundamental level, antiferroelectrics have their own distinctive type of domain walls: while ferroelectric domain walls can be seen as non-polar sheets separating polar domains of opposite orientation, in antiferroelectrics the opposite is true: the domains are non-polar (or antipolar) but the domain walls are polar. The internal symmetry of these antiferroelectric phase boundaries can be very sophisticated and, in the case of the archetypal antiferroelectric PbZrO3, it leads to the emergence of ferrielectricity. In my seminar I will attempt to give an overview of the general physics of antiferroelectrics, their functionalities, and their emerging domain wall properties.
REFS
1. Perez-Tomas, M. Lira-Cantu, G. Catalan, Above-Bandgap Photovoltages in Antiferroelectrics. Advanced Materials 28, 9644 (2016).
2. P. Vales-Castro, R. Faye, M. Vellvehi, Y. Nouchokgwe, X. Perpiñà, J.M. Caicedo, X. Jordà, K. Roleder, D. Kajewski, A. Perez-Tomas, E. Defay, G. Catalan; Origin of large negative electrocaloric effect in antiferroelectric PbZrO3, Physical Review B 103, 054112 (2021).
3. Ying Liu, Ranming Niu, Andrzej Majchrowski, Krystian Roleder, Julie M. Cairney, Jordi Arbiol, Gustau Catalan, Translational boundaries as incipient ferrielectric domains in antiferroelectric PbZrO3. https://arxiv.org/abs/2211.09115 (2022).
Coffee and pastries will be served
ICREA and ICN2-Institut Català de Nanociència i Nanotecnologia, Barcelona, Catalonia.