Polar topologies, such as vortex and skyrmion, have attracted significant interest due to their unique physical properties and promising applications in high-density memory devices. To date, all known polar vortices are present in or induced by ferroelectric materials. In this study, we find polar vortex arrays in paraelectric SrTiO. Using multislice electron ptychography, the evolution of vorticity along the vortex axis is revealed in twisted bilayers of SrTiO with deep-sub-angstrom resolution and one picometer accuracy. The surprising finding of polar vortices in a paraelectric crystal opens up opportunities for polarization physics and corresponding new devices.
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http://dx.doi.org/10.1038/s41467-024-55328-1 | DOI Listing |
Nat Commun
January 2025
Space and Earth Observation Centre, Finnish Meteorological Institute, Helsinki, Finland.
Solar driven energetic particle precipitation (EPP) is an important factor in polar atmospheric ozone balance and has been linked to ground-level regional climate variability. However, the linking mechanism has remained ambiguous. The observed and simulated ground-level changes start well before the processes from the main candidate, the so-called EPP-indirect effect, would start.
View Article and Find Full Text PDFAppl Environ Microbiol
January 2025
Clinical Infection Department, Chelsea and Westminster Hospital NHS Foundation Trust, London, United Kingdom.
Unlabelled: Remote polar regions offer unique opportunities and significant challenges for antimicrobial resistance research in a near-pristine environment. While core microbiology techniques continue to have an important role in supporting environmental research, the severe cold climate presents considerable challenges to laboratory research. We explore adaptations required for core bacteriology investigations in polar regions on an unsupported remote expedition c.
View Article and Find Full Text PDFThis Letter introduces a method for identifying the fast axis and phase retardation of wave plates by means of polarization common-path vortex interferometry. The technique utilizes a composite polarized vortex beam interacting with the wave plate under test. By analyzing the azimuth angle of the dark fringe in the interference pattern, the wave plate's characteristics are accurately extracted.
View Article and Find Full Text PDFOptical misalignment between transmitter and receiver leads to power loss and mode crosstalk in a mode division multiplexing (MDM) free-space optical (FSO) link. We report both numerical simulations and experimental results on the propagation performance of two typical vector beams, C-point polarization full Poincaré beams (FPB), and V-point polarization cylindrical vector beams (CVB), compared to homogeneous polarization scalar vortex beams (SVB) under optical misalignment. The FSO communication performance under misalignment using different transmit beams is evaluated in terms of power loss, mode crosstalk, power penalty, etc.
View Article and Find Full Text PDFNano Lett
January 2025
Department of Engineering Mechanics, Zhejiang University, Hangzhou, 310027 Zhejiang, China.
Chiral vortices and their phase transition in ferroelectric/dielectric heterostructures have drawn significant attention in the field of condensed matter. However, the dynamical origin of the chiral phase transition from achiral to chiral polar vortices has remained elusive. Here, we develop a phase-field perturbation model and discover the softening of out-of-plane vibration mode of polar vortices in [(PbTiO)/(SrTiO)] superlattices at a critical epitaxial strain or temperature.
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