Long-range symmetry breaking in embedded ferroelectrics

• Published in: Nature materials 2018-09, Vol.17 (9), p.814-819
• Main Authors: Simons, Hugh, Haugen, Astri Bjørnetun, Jakobsen, Anders Clemen, Schmidt, Søren, Stöhr, Frederik, Majkut, Marta, Detlefs, Carsten, Daniels, John E., Damjanovic, Dragan, Poulsen, Henning Friis
• Format: Article
• Language: English
• Subjects: 639/301/1005/1006; 639/301/1023/1024; 639/301/119/996; 639/301/930/2735; Barium titanates; Biomaterials; Broken symmetry; Characteristic functions; Chemistry and Materials Science; Condensed Matter Physics; Domain walls; Ferroelectric materials; Ferroelectricity; Ferroelectrics; Grain boundaries; Magnetic fields; Materials Science; Nanotechnology; Optical and Electronic Materials; Symmetry; X ray microscopy
• ISSN: 1476-1122; 1476-4660
• DOI: 10.1038/s41563-018-0116-3

The characteristic functionality of ferroelectric materials is due to the symmetry of their crystalline structure. As such, ferroelectrics lend themselves to design approaches that manipulate this structural symmetry by introducing extrinsic strain. Using in situ dark-field X-ray microscopy to map lattice distortions around deeply embedded domain walls and grain boundaries in BaTiO 3 , we reveal that symmetry-breaking strain fields extend up to several micrometres from domain walls. As this exceeds the average domain width, no part of the material is elastically relaxed, and symmetry is universally broken. Such extrinsic strains are pivotal in defining the local properties and self-organization of embedded domain walls, and must be accounted for by emerging computational approaches to material design. Ferroelectricity can be modified by domain wall strain fields that extend over nanometres. Here, with X-ray microscopy, strain fields over several micrometres are observed in BaTiO 3 , suggesting ferroelectricity is globally altered throughout the material.