A beautiful twist on condensed matter
Discussion meeting organised by Professor Christos Panagopoulos, Professor Neil Mathur and Professor Ramamoorthy Ramesh ForMemRS.
There is currently great interest in the fundamental physics of topologically complex and elegant patterns that can arise or be created in magnetic, ferroelectric, and liquid crystal materials. This meeting will explore similarities and differences between the complex order in these classes of material. We will also focus on how the complex patterns may be exploited to encode and transmit information.
Programme
The programme, including speaker biographies and abstracts, will be available soon. Please note the programme may be subject to change.
Poster session
There will be a poster session from 5pm on Tuesday 28 April 2026. If you would like to present a poster, please submit your proposed title, abstract (up to 200 words), author list, and the name of the proposed presenter and institution no later than Friday 27 March 2026.
Attending the event
This event is intended for researchers in relevant fields.
- Free to attend
- Both virtual and in-person attendance is available. Advance registration is essential. Please register via Eventbrite for a ticket
- Lunch is available on both days of the meeting for an optional £25 per day. There are plenty of places to eat nearby if you would prefer purchase food offsite. Participants are welcome to bring their own lunch to the meeting
Enquiries: Scientific Programmes team.
Image credit: iStock.com / merrymoonmary
Schedule
Chair
Professor Christos Panagopoulos
Nanyang Technological University, Singapore
Professor Christos Panagopoulos
Nanyang Technological University, Singapore
Christos Panagopoulos received his PhD from the University of Cambridge (Trinity College) and is Professor of Physics and Applied Physics at Nanyang Technological University, Singapore. His research programme is directed toward the discovery and characterisation of materials with complex quantum order, the advancement of experimental methodologies capable of probing correlations across diverse length and time scales, and the development of theoretical frameworks elucidating the role of wavefunction geometry and topology in governing material properties. By integrating these approaches, he establishes rigorous connections between the underlying quantum architecture of matter and emergent device functionalities, thereby contributing to both fundamental understanding and prospective technological innovation.
| 08:55-09:00 |
Welcome by the Royal Society and lead organiser
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| 09:00-09:30 |
Reversible fusion of particle-like chiral nematic and magnetic vortex knots
Vortex knots have been seen decaying in many physical systems. Here we describe topologically protected vortex knots, which remain stable and undergo fusion and fission while conserving a topological invariant analogous to that of baryon number. While the host medium, a chiral nematic liquid crystal, exhibits intrinsic chirality, cores of the vortex lines are structurally achiral regions where twist cannot be defined. We refer to them as "dischiralation" vortex lines, in analogy to dislocations and disclinations in ordered media where, respectively, positional and orientational order is disrupted. Fusion and fission of these vortex knots, which we reversibly switch by electric pulses, vividly reveal the physical embodiments of knot theory's concepts like connected sums of knots. Our findings provide insights into related phenomena in fields ranging from cosmology to particle physics and can enable applications in electro-optics and photonics, where such fusion and fission processes can be used for controlling light. 
Professor Ivan SmalyukhUniversity of Colorado Boulder, US
Professor Ivan SmalyukhUniversity of Colorado Boulder, US Ivan I Smalyukh is a tenured professor at the Department of Physics, University of Colorado at Boulder, which he joined in 2007 (promoted from Assistant to Associate Professor with tenure in 2014 and from Associate to Full Professor in 2017). He is also the Founding Director of the International Institute for Sustainability with Knotted Chiral Meta Matter, as well as the founding fellow of Renewable Sustainable Energy Institute, a joint institute of CU-Boulder and NREL. He is an elected fellow of APS, AAAS, Optica and SPIE. He received many awards, including the Bessel and Glenn Brown Awards, Gray Medal, NASA iTech award and Mid-Career Award of the International Liquid Crystal Society, the PECASE Award from the Office of Science and Technology of the White House and the GSoft Award from the American Physical Society. |
| 09:30-09:45 |
Discussion
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| 09:45-10:15 |
Topological defects in nematic colloidal crystals
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| 10:15-10:30 |
Discussion
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| 10:30-11:00 |
Break
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| 11:00-11:30 |
Lorentz electron ptychography on centrosymmetric skyrmions
Electrons play a pivotal role in stabilizing matter, but they are also tools that can reveal the underlying physics of complex systems from high energy physics to condensed matter. Electrons can be used as imaging probes, where properties of matter such as ferroelectricity, magnetism or topology can be observed atom-by-atom. In this talk, I will discuss a new type of electron probe which can image the chiral order of centrosymmetric magnetic skyrmions called Lorentz electron ptychography, an iterative phase retrieval imaging technique for magnetic materials. In particular, my research focuses on amorphous layered thin films of FeGdPt, which have been shown to form centrosymmetric skyrmions with a predicted internal Bloch wall and Néel caps. Using simulation and experimental results from Lorentz electron ptychography and four-dimensional scanning transmission electron microscopy, I show that this structure does indeed have a hybrid Bloch and Néel skyrmion structure, as predicted from micromagnetic simulations. Finally, I will also show how electron ptychography can improve resolution beyond the numerical aperture of the electromagnetic lenses to the sub-angstrom limit in a conventional electron microscope. Using this technique, I essentially develop a ‘computation lens’ approach to imaging, opening opportunities to explore new physics in emergent materials beyond physical lenses in a cost-effective manner, and thus expanding access to high-resolution imaging approaches to a broader range of institutions. 
Professor Kayla NguyenUniversity of Oregon, US
Professor Kayla NguyenUniversity of Oregon, US Dr Kayla Nguyen has made a tremendous impact in the field of transmission electron microscopy. She earned her undergraduate degree in Physics from the University of California Santa Barbara, and PhD from Cornell University. At Cornell, she provided a critical role in the development of a novel pixel array detector for electron microscopes with unprecedented dynamic range, sensitivity, and speed. This new detector has been licensed and sold around the world by Thermo Fisher Scientific. During her postdoctoral fellowship at the University of Illinois Urbana-Champaign, she won the L’Oreal For Women in Science Postdoctoral Fellowship and was named a promising Asian researcher by The Japan Times. In 2023, she became an Assistant Professor at the University of Oregon where she received a coveted Arnold and Mabel Beckman Young Investigator, the Army Research Office Early Career Program Award, the National Scientific Foundation MRI for a new TEM, and industry sponsored research from Intel to continue her cutting edge work. Her passion for science extends beyond the laboratory setting, towards developing accessible pathways for young scientists in STEM. |
| 11:30-11:45 |
Discussion
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| 11:45-12:15 |
Neutron spectroscopy
Professor Catherine PappasDelft University of Technology, The Netherlands
Professor Catherine PappasDelft University of Technology, The Netherlands Catherine (Katia) Pappas joined 2009 Delft University of Technology to lead the section Neutron and Positron Methods in Materials (NPM2), within the Faculty of Applied Sciences. Her field of expertise is in neutron scattering science and techniques, with focus on high-resolution (neutron spin echo) spectroscopy and polarized neutrons. Besides neutron instrumentation, her scientific interests are in the field of magnetism and chiral magnetism, and the field of skyrmions. Before Delft Katia spent several years at the Hahn-Meitner Institute – nowadays Helmholtz Zentrum Berlin – where she was involved in numerous large scale neutron instrumentation projects. She was deputy director of the Berlin Neutron Scattering Center and head of the "Neutron Instruments and Methods" department. In Delft, she was again the initiator of several big instrumentation projects, such as the neutron powder diffractometer PEARL or the multipurpose instrument LARMOR, a Dutch-UK collaboration, which is being built at the UK neutron source ISIS and is supported by the Dutch Science Foundation (NWO). |
| 12:15-12:30 |
Discussion
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Chair
Professor Karin Everschor-Sitte
University of Duisburg-Essen, Germany
Professor Karin Everschor-Sitte
University of Duisburg-Essen, Germany
| 13:30-14:00 |
X-ray tomography
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| 14:00-14:15 |
Discussion
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| 14:15-14:45 |
Ferromagnetic/ferroelectric chiral architectures
Professor Jiamian HuUniversity of Wisconsin-Madison, US
Professor Jiamian HuUniversity of Wisconsin-Madison, US Dr Jiamian Hu is an Associate Professor in the Department of Materials Science and Engineering at the University of Wisconsin (UW)-Madison. Dr Hu received the Vilas Associate Award for research from UW-Madison, the Innovation Award from the Wisconsin Alumni Research Foundation, the Robert L Coble Award for Young Scholars from the American Ceramic Society, and the National Science Foundation CAREER award. Dr Hu has published over 100 peer-reviewed articles and is the lead inventor of five granted US Patents. His current research activities include mesoscale modeling of ferroic (magnetic, ferroelectric, and multiferroic) materials, polar semiconductors, and the resulting quantum and microelectronic devices, microstructure formation and evolution under nonequilibrium conditions, and microstructure informatics. Dr Hu served as an Associate Editor for the Journal of Materials Research and an Editorial Board Member of Journal of Physics D: Applied Physics. |
| 14:45-15:00 |
Discussion
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| 15:00-15:30 |
Break
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| 15:30-16:00 |
Magnetic tunnel junctions in chiral ferromagnets
Dr Stefania PizziniInstitut Néel, CNRS, France
Dr Stefania PizziniInstitut Néel, CNRS, France |
| 16:00-16:15 |
Discussion
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| 16:15-17:00 |
Poster flash talks
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Chair
Dr Olga Kazakova
National Physical Laboratory, UK
Dr Olga Kazakova
National Physical Laboratory, UK
Olga Kazakova is a Fellow of the National Physical Laboratory (NPL), London, UK, and currently serves as Chair of NPL’s Senior Science College. Her research lies at the intersection of Materials Science and Quantum Technology, with a particular focus on materials for quantum applications. Previously, Olga has led pioneering work in advanced imaging techniques for functional nanoscale studies, the development of novel sensors for environmental monitoring, life sciences, and food safety, as well as metrological innovations. She is the author of approximately 200 peer-reviewed publications and has delivered over 180 presentations at scientific conferences, including more than 80 invited talks and seminars. Her contributions have been recognised with numerous national and international awards, such as the Intel European Research and Innovation Award, NPL Rayleigh Award, and Serco Global Pulse Award. Olga is a Fellow of the Institute of Physics and holds a Professorship at the University of Manchester.
| 09:00-09:30 |
Diamond magnetometry
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| 09:30-09:45 |
Discussion
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| 09:45-10:15 |
Merons and bimerons in an antiferromagnet
Professor Paolo Radaelli, University of Oxford, UK
Professor Paolo Radaelli, University of Oxford, UKPaolo G Radaelli is the Dr Lee’s Professor of Experimental Philosophy at the Department of Physics, Oxford University. Following a Laurea degree at the Università degli Studia di Milano and a PhD at Illinois Institute of Technology, Professor Radaelli has held posts at the Argonne National Laboratory, CNRS Grenoble, the Institute Laue–Langevin and the ISIS Facility at the Rutherford Appleton Laboratory. His main interest is the study of transition metal oxides displaying novel physical phenomena, such as high-temperature superconductivity, “colossal” magneto-resistance or multiferroics behaviour, with the potential of device applications. |
| 10:15-10:30 |
Discussion
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| 10:30-11:00 |
Break
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| 11:00-11:30 |
Quantum magnets for Skyrmion qubits
Dr Christina PsaroudakiEcole Normale Supérieure Paris, France
Dr Christina PsaroudakiEcole Normale Supérieure Paris, France |
| 11:30-11:45 |
Discussion
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| 11:45-12:15 |
Neuromorphics in chiral ferrimagnets
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| 12:15-12:30 |
Discussion
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Chair
Professor Jorge Íñiguez-González
Luxembourg Institute of Science and Technology, Luxembourg
Professor Jorge Íñiguez-González
Luxembourg Institute of Science and Technology, Luxembourg
Jorge Íñiguez-González is a group leader at the Luxembourg Institute of Science and Technology and affiliate full professor of Physics at the University of Luxembourg. His work focuses on the application of quantum simulation methods to problems at the frontier of materials science, including extensive studies of functional nanomaterials as well as methodological developments for predictive large-scale simulations. Recent highlights include the discovery of topological electric quasiparticles or “electric skyrmion bubbles”. He is a Fellow of the American Physical Society “For ground-breaking contributions to the computational theory of ferroelectric and multiferroic materials.
| 13:30-14:00 |
Toroidal topologies in ferroelectric polymers and their electrical controls
Strong dielectric anisotropy in ferroelectric materials normally prefers rigid dipole alignment with crystallographic axes and lead to simple polar structures. Lamellar crystals of ferroelectric polymers based on poly(vinylidene fluoride) comprise molecular chains preferentially aligned along a common lattice direction, which preserves a rotational degree of freedom about the chain backbone. I will explain how dipoles in ferroelectric polymers can therein be frustrated into toroidal topologies, either mechanically via biaxial tensile strain, or chemically through conformational disorder. When an out-of-plane electric field or mechanical pressure is applied with a small magnitude, the toroidal topology undergoes continuous rotation without being destroyed. In contrast, an in-plane electric field annihilates the toroidal topology, which could be reversible created upon field removal. Given that polymers absorb infrared radiation in a selective manner, these field-modified topological states can be read out using plane-polarised radiation. The ability to rotate, erase, and create these toroidal textures offers prospects for reconfigurable electronic and photonic devices. 
Dr Mengfan GuoUniversity of Cambridge, UK
Dr Mengfan GuoUniversity of Cambridge, UK Dr Mengfan Guo is a Goldsmiths' Early Career Research Fellow at University of Cambridge, and a former Royal Society Newton International Fellow. He received BS and PhD degrees from Tsinghua University in 2016 and 2021, respectively. His research focuses on polar materials, particularly the static and dynamic arrangements of electrical dipoles that give rise to emergent properties. A research highlight is the discovery of toroidal topologies in ferroelectric polymers. His work has been published in Science, Nature Energy, Nature Nanotechnology etc. He has been recognized as an Outstanding Graduate in Beijing, a Tsinghua Top Academic Talent, and a recipient of the Excellent Doctor Degree Dissertation Award in both Beijing and Tsinghua University. |
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| 14:00-14:15 |
Discussion
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| 14:15-14:45 |
Domain walls in polar vortices
Professor Javier JunqueraUniversidad de Cantabria, Spain
Professor Javier JunqueraUniversidad de Cantabria, Spain Professor Javier Junquera is a theoretical condensed matter physicist and core developer of the SIESTA code for large-scale first-principles simulations. His research combines methodological innovation with the application of ab-initio and “second-principles” approaches to ferroelectric and topological materials. He has made key contributions to understanding size effects, depolarizing fields, and band alignment in oxide nanostructures, and to predicting emergent polar textures (such as polar skyrmions and vortex arrays) in ferroelectric superlattices in collaboration with the Ramesh group at UC Berkeley. These studies unveiled novel topological phases in polar materials, featuring negative capacitance, chirality, and phase coexistence. His ongoing work focuses on multiscale “second-principles” simulations coupling electronic and ionic degrees of freedom to access mesoscale phenomena with first-principles accuracy. Fellow of the American Physical Society in the division of Material Science. |
| 14:45-15:00 |
Discussion
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| 15:00-15:30 |
Break
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| 15:30-16:00 |
Moiré polar topologies in twisted oxide membranes
The recent realization of membranes of perovskite oxides, has enabled their assembly into twisted homo bilayers. In twisted BaTiO3 membranes, these inhomogeneous strain patterns underlay the formation of an array of ferroelectric vortices driven by the flexoelectric coupling of polarization to strain gradients [1]. Surprisingly, the shear interaction developing at the interface, driven by the mostly incoherent atomic registry between the two twisted layers, propagate into the layers, relaxing over distances which can be as long as tens of nanometers. The decaying nonhomogeneous strain triggers profound changes in the polarization landscape which evolves from a pure rotational polarization pattern with alternating ferroelectric vortices and antivortices to a superposition of a vortex lattice and a homogeneous polarization component. Yet, flexoelectricity is a universal phenomenon which may render polar landscapes in non-ferroelectric materials. Here we report a flexoelectrically induced polar topology in twisted membranes of SrTiO3, a paraelectric centrosymmetric material. The polar landscape triggered by twisting is also supported by machine learned force fields based on first-principles calculations. We further show that the strain and polarization patterns in top and bottom layers are correlated in a way which breaks inversion and mirror symmetries thus unlocking a chirality degree of freedom. [1] G. Sanchez-Santolino et al. Nature 626, 529 (2024) |
| 16:00-16:15 |
Discussion
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| 16:15-17:00 |
Panel discussion/overview (future directions)
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