A tale from the umpteenth ferroelectric revival: electric quasiparticles

11.03.2025 13:00 – 14:30

Ferroelectricity has been studied for over a century, yet it continues to captivate our imagination with a seemingly endless parade of novel materials and striking behaviors. Over the past years many new compounds – from simple wurtzites and fluorites to various families of 2D materials – have been shown to possess a spontaneous and switchable electric polarization, the hallmark of ferroelectricity. Today we even have examples of ferroelectric metals, traditionally deemed impossible, with a robust and reversible polar distortion despite screening by mobile charges. The list of emerging properties is similarly impressive, from light-induced magnetization to voltage amplification, from piezocatalysis to “topotactic” ferroelectricity. Alongside the new materials and properties come exciting technological prospects in many areas, from electronics, computing and communications to sensing, energy harvesting or catalysis.
In this talk I will try to convey the current excitement in the field of ferroelectrics and related materials, giving an overview of the activities in my group. I will then focus on an ongoing breakthrough where we are playing a pivotal role: the prediction and experimental demonstration of electric skyrmion bubbles – the electric counterpart of magnetic skyrmions. I will explain how elastic and electric constraints at the nanoscale enable the stabilization of non-collinear electric dipole arrangements, which can be leveraged to create topological objects equivalent to magnetic skyrmions. I will show simulation evidence that these electric skyrmion bubbles (e-bubbles) can be brought into regimes where they exhibit spontaneous stochastic motion, thus behaving as long-lived Brownian quasiparticles. I will further show how the application of realistic electric field gradients or waves makes it possible to bias the movement of said Brownian e-bubbles, yielding net drift velocities in the range of 100 m/s. I will discuss the available experimental evidence for e-bubbles, as well as the remaining outstanding challenges. I will also address similarities and differences with magnetic skyrmions. Finally, I will outline the exciting scientific prospects these electric quasiparticles open, e.g., in the field of neuromorphic computing.
My main collaborators in these works are M.A.P. Gonçalves (formerly at LIST, now at the Czech Academy of Sciences) and Hugo Aramberri (LIST). Collaborators at the University of Cantabria (Junquera), UC Berkeley/Rice (Ramesh, Martin) and elsewhere were involved in some of the projects. Work in Luxembourg was funded by the Luxembourg National Research Fund. For published articles and further information, please visit https://sites.google.com/site/jorgeiniguezresearch/

Lieu

Bâtiment: Ecole de Physique

Auditoire Stuckelberg

entrée libre