Symmetry, Topology, and Magnetoelectric Multiferroicity

Date : Feb 7 2026 13:00 - 15:00 EST
Title: Symmetry, Topology, and Magnetoelectric Multiferroicity — Ferroelectric 'Tweezers' for Quantum Magnetism in Hexagonal Ferrites

Abstract: The scalability of future quantum and spintronic hardware is currently facing a "physical wall": the challenges of excessive heat dissipation and environmental magnetic noise. To overcome these barriers, materials where magnetism can be controlled with high precision and minimal energy will be highly desirable. Magnetoelectric multiferroic hexagonal rare-earth ferrites (h-RFeO3, R: rare earth) have emerged as an important platform for this mission, offering a unique "playground" where symmetry and topology dictate functionality. In this talk, I will provide a comprehensive overview of research progress on these materials over the last decade. We will explore how a specific structural transition—trimerization—breaks symmetry to create a robust state known as improper ferroelectricity as well as weak ferromagnetism. The coupling between the ferroelectric and magnetic orders leads to a "ferroelectric tweezer" effect, where the material's ferroelectric domain spatially anchors and manipulates magnetic domains. Furthermore, we will address the "readout challenge": how to detect the diminutive magnetic moments inherent in these systems. I will show how the non-coplanar spin topology acts as a signal amplifier, enabling high-fidelity readout of magnetic states through spin-transport. By understanding the "solid science" of these complex oxides, we can define the roadmap for a new generation of stable, low-power topological electronics.
Biography: Xiaoshan Xu is Susan J. Rosowski Associate Professor from Department of Physics and Astronomy at University of Nebraska-Lincoln. He graduated from Nanjing University in 1997 and 2000 with his bachelor’s and master’s degrees respectively. He received his Ph. D. in Georgia Institute of Technology in 2007. After that, he worked at the University of Tennessee as a postdoctoral researcher and Oak Ridge National Lab as an R&D Associate. He joined the University of Nebraska in 2013. He is a recipient of the Eugene P. Wigner Fellowship of the Oak Ridge National Lab, NSF Early Career Award, and DOE Early Career Award. His research interests include oxide and organic thin film growth, spintronics, multiferroics, and quantum materials.

Moderator: Dr. Sebastian Zajac, member of QPoland