Ferroelectrics are characterized by domain structures as are other ferroics. At the nanoscale though, ferroelectrics may exhibit non-trivial or exotic polarization configurations under proper electrostatic and elastic conditions. These polar states may possess emerging properties not present in the bulk compounds and are promising for technological applications. Here, the observation of rotational polarization topologies at the nanoscale by means of aberration-corrected scanning transmission electron microscopy is reported in BaTiO/SrTiO superlattices grown on cubic SrTiO(001). The transition from a highly homogeneous polarization state to the formation of rotational nanodomains has been achieved by controlling the superlattice period while maintaining compressive clamping of the superlattice to the cubic SrTiO substrate. The nanodomains revealed in BaTiO prove that its nominal tetragonal structure also allows rotational polar textures.
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http://dx.doi.org/10.1039/c9nr08050c | DOI Listing |
Spectrochim Acta A Mol Biomol Spectrosc
January 2025
Instituto de Ciencia de Materiales de Madrid (ICMM), CSIC, Cantoblanco, 28049 Madrid, Spain; Departamento de Química Orgánica y Química Inorgánica, Universidad de Alcalá, 28805 Alcalá de Henares, Madrid, Spain. Electronic address:
7,7'-Diazaisoindigos are π-conjugated compounds but with poor luminescence properties. Their poor luminescence is generally attributed to the twisting around the central C-C bond in the excited state which favors non-radiative decay. We have found an unusual high fluorescence quantum yield (Φ ≈ 15 %) in a N,N‑Octyl-7,7'-diazaisoindigo derivative incorporating two triphenylamine (TPA) subunits at 5,5'-positions (called compound 12).
View Article and Find Full Text PDFNat Commun
January 2025
Department of Optics and Optical Engineering, University of Science and Technology of China, Hefei, China.
The spin angular momentum (SAM) plays a significant role in light-matter interactions. It is well known that light carrying SAM can exert optical torques on micro-objects and drive rotations, but 3D rotation around an arbitrary axis remains challenging. Here, we demonstrate full control of the 3D optical torque acting on a trapped microparticle by tailoring the vectorial SAM transfer.
View Article and Find Full Text PDFSci Total Environ
January 2025
Department of Oncobiology and Epigenetics, Faculty of Biology and Environmental Protection, University of Lodz, Lodz, Poland; Laboratory of Transcriptional Regulation, Institute of Medical Biology PAS, Lodz, Poland. Electronic address:
Sensors (Basel)
January 2025
Department of Electrical Engineering, Indian Institute of Technology Madras, Chennai 600036, India.
In the last decade, substantial progress has been made to improve the performance of optical gyroscopes for inertial navigation applications in terms of critical parameters such as bias stability, scale factor stability, and angular random walk (ARW). Specifically, resonant fiber optic gyroscopes (RFOGs) have emerged as a viable alternative to widely popular interferometric fiber optic gyroscopes (IFOGs). In a conventional RFOG, a single-wavelength laser source is used to generate counter-propagating waves in a ring resonator, for which the phase difference is measured in terms of the resonant frequency shift to obtain the rotation rate.
View Article and Find Full Text PDFSensors (Basel)
December 2024
Research Center of Applied Electromagnetics, Nanjing University of Information Science and Technology, Nanjing 210044, China.
We present a novel photoreconfigurable metasurface designed for independent and efficient control of electromagnetic waves with identical incident polarization and frequency across the entire spatial domain. The proposed metasurface features a three-layer architecture: a top layer incorporating a gold circular split ring resonator (CSRR) filled with perovskite material and dual -shaped perovskite resonators; a middle layer of polyimide dielectric; and a bottom layer comprising a perovskite substrate with an oppositely oriented circular split ring resonator filled with gold. By modulating the intensity of a laser beam, we achieve autonomous manipulation of incident circularly polarized terahertz waves in both transmission and reflection modes.
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