Seminar Date: Tuesday, June 18, 2024
Time: 11:00 am
Location: 67-3111 & Zoom
Talk Title: Structure-Property Relations in the Polar Vortex System.
Zoom recording (available for 30 days)
Abstract:
For a long time, ferroelectric analogues to topological spin textures were thought to be nonexistent and impossible to stabilize. However, over the past decade, we have witnessed dramatic progress in our understanding of such dipolar surface textures. In 2016, the discovery of ferroelectric vortices in dielectric-ferroelectric superlattices led to further discoveries of numerous novel states of matter and exotic functionalities. Here, I will explore how careful control over elastic and electrical energies allows for the stabilization of topological polar textures, and I will examine the structure of the polar vortices from the atomic scale to the mesoscale. With this detailed understanding of the vortex lattice, we can understand the emergence of numerous properties, namely macroscopic ferroelectricity, chirality, and ultrafast dynamical responses. Finally, I will present open questions and potential pathways forward in the nascent field of topological polar textures.
Bio:
Piush Behera is currently a graduating Ph.D. student from Prof. Ramamoorthy Ramesh’s group at UC Berkeley. There he focuses on the physics of thin film ferroelectrics, specifically examining the emergent properties of ferroelectric surface textures. While topological textures in magnetic systems (i.e., vortices and skyrmions) have been widely studied, their ferroelectric counterparts have only recently emerged with the discovery of dipolar vortices occurring in 2016. Here, we examine the detailed atomic-scale and mesoscale structure of the polar vortex system formed in ferroelectric-dielectric superlattices. Through a better understanding of the vortex ordering, we can also understand their novel properties such as negative capacitance, collective dynamics, and chirality.