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An international team of scientists published a new review article titled “Topological foundations of ferroelectricity” in the journal Physics Reports (Impact Factor: 23.9). The article explores the fundamental role of topology in ferroelectric materials. Researcher Dr. Anna Razumnaya from Jozef Stefan Institute, in collaboration with researchers from the University of Picardie, IFW Dresden, the University of Toronto, and Terra Quantum AG, provided a groundbreaking framework for understanding and classifying complex polarization structures in nanostructured ferroelectrics, paving the way for future technological applications. Ferroelectric materials have long been studied for their unique electrical properties and applications in memory devices, sensors, and energy-efficient electronics. Recent discoveries have revealed that these materials can host a variety of exotic topological states, including vortices, skyrmions, and Hopfions. By drawing parallels between hydrodynamics and electrostatics, the study introduces a comprehensive classification of these topological states and their impact on the behavior of ferroelectrics.

This research demonstrates how fundamental topological concepts, such as helicity, fibration, and ergodicity, can be applied to ferroelectric materials to better understand and manipulate their polarization structures. This work expands the theoretical foundations of ferroelectricity and opens new avenues for the design of next-generation functional materials. By bridging topology with condensed matter physics, this study opens new prospects for the development of polar materials, including traditional ferroelectrics and newly discovered soft ferroelectric materials, while also advancing the frontiers of their potential applications in cutting-edge electronic devices.… Read the rest “Topological foundations of ferroelectricity”

Bose-Einstein condensates subjected to modulation of the interaction between atoms exhibit the emergence of density waves and matter-wave jets with a velocity proportional to the square root of the modulation frequency. In the newly published paper, the authors present the experimental observation of higher-order incommensurable “golden” matter-wave jets emerging from a Bose-Einstein condensate exposed to a single frequency interaction modulation. The formation of higher-order jets in quasi-one-dimensional geometry is modelled using numerical one-dimensional (1D) Gross-Pitaevskii equation simulation. The authors explore the process of jet formation experimentally and theoretically for a wide range of modulation amplitudes and frequencies and establish a phase diagram delineating different regimes of jet formation.

DOI: https://doi.org/10.1038/s42005-025-01937-1

Using scanning tunneling microscopy and spectroscopy we demonstrate a revival of magnetism in 7-armchair nanoribbon by unpassivated atoms at the termini. Namely, a pair of intense Kondo resonances emerges at the peripheries of zigzag terminus revealing the many-body screening effects of local magnetic moments. Although Kondo resonance originates from a missing local orbital, it extends to a distance of 2.5 nm along the edge of the ribbon. The results are complemented by density functional theory calculations which suggest a possible coupling between Kondo states despite screening effects of substrate electrons. These findings indicate a possibility to restore intrinsic magnetic ordering in graphene nanoribbon without major structural modifications

DOI: https://doi.org/10.1038/s41598-024-62624-9

Smectic A (SmA) liquid crystals can be viewed as model systems for lamellar structures. They bridge the study of broken orientational symmetry, the statistical mechanics of membranes, and the long-range periodic order in crystals. Among others, they provide an arena to systematically study the effects of nonlinear elasticity. We demonstrated that a nonlinear energy description is required which is not captured in the classical Landau-de Gennes-Ginsburg model in order to explain the observed layer spacing of highly curved SmA layers. Using X-ray diffraction, we quantitatively determined the dilation of bent layers distorted by antagonistic anchoring. We showed that combined X-ray measurements and theoretical modeling allow for the quantitative determination of the number of curved smectic layers and their thickness in dilated regions.

DOI: https://doi.org/10.1103/PhysRevLett.134.018101

To visualize the intrinsic band structure of armchair graphene nanoribbon and verify theories, the terminus is covalently bonded to Au-coated tip. Tunneling spectroscopies with these suspended nanoribbons exhibit symmetric onsets of conduction and valence bands around zero bias. From these results, a value of 2.78 eV for the band gap is determined which agrees very well with theoretical calculations.

Interestingly, the formation of C—Au bond suppresses Schottky contact resistance which is one of the essential prerequisites for future nanoribbon electronics.

DOI: https://onlinelibrary.wiley.com/doi/10.1002/pssr.202470030