Nano-structured ferroelectrics are being increasingly recognized as highly tunable materials that can display states and properties markedly different from those of the bulk. In this talk I will describe our latest simulation work on ferroelectric/dielectric PbTiO3/SrTiO3 superlattices, a convenient model system that has been shown to present the most interesting behaviors. For example, I will show how the electric boundary conditions imposed by the dielectric layers make it possible to induce different types of multi-domain states in the ferroelectric, including some featuring electric skyrmions [1].  Further, we will see that the response of the ferroelectric layers can be engineered to achieve optimal antiferroelectric-like performance (useful for energy storage) [2] or, alternatively, to maximize the so-called negative-capacitance and voltage-amplification effects (of great interest for, e.g., the development of low-power field-effect transistors) [3].


Work done in collaboration with Hugo Aramberri, Mónica Graf and Natalya S. Fedorova (LIST) and M.A.P. Gonçalves (formerly at LIST, now at the Czech Academy of Sciences). Collaborators at the University of Cantabria (Junquera), UC Berkeley (Ramesh) and elsewhere were involved in some of the projects. Work in Luxembourg funded by the Luxembourg National Research Fund through projects C18/MS/12705883 “REFOX”, INTER/RCUK/18/12601980 and FNR/C15/MS/10458889 “NEWALLS”.

[1] Observation of room-temperature polar skyrmions, S. Das et al., Nature 568, 368 (2019).
[2] Ferroelectric/paraelectric superlattices for energy storage, Hugo Aramberri, Natalya S. Fedorova and Jorge Íñiguez, https://arxiv.org/abs/2112.00745
[3] Giant voltage amplification from incipient ferroelectric states, Mónica Graf, Hugo Aramberri, Pavlo Zubko and Jorge Íñiguez, https://arxiv.org/abs/2201.07104