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Title: Phase coexistence and electric-field control of toroidal order in oxide superlattices

Systems that exhibit phase competition, order parameter coexistence, and emergent order parameter topologies constitute a major part of modern condensed-matter physics. Here, by applying a range of characterization techniques, and simulations, we observe that in PbTiO 3/SrTiO 3 superlattices all of these effects can be found. By exploring superlattice period-, temperature- and field-dependent evolution of these structures, we observe several new features. First, it is possible to engineer phase coexistence mediated by a first-order phase transition between an emergent, low-temperature vortex phase with electric toroidal order and a high-temperature ferroelectric a 1/a 2 phase. At room temperature, the coexisting vortex and ferroelectric phases form a mesoscale, fibre-textured hierarchical superstructure. The vortex phase possesses an axial polarization, set by the net polarization of the surrounding ferroelectric domains, such that it possesses a multi-order-parameter state and belongs to a class of gyrotropic electrotoroidal compounds. Finally, application of electric fields to this mixed-phase system permits interconversion between the vortex and the ferroelectric phases concomitant with order-of-magnitude changes in piezoelectric and nonlinear optical responses. Here, our findings suggest new cross-coupled functionalities.
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  1. Univ. of California, Berkeley, CA (United States); Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
  2. Pennsylvania State Univ., University Park, PA (United States)
  3. Argonne National Lab. (ANL), Argonne, IL (United States)
  4. Univ. of California, Berkeley, CA (United States)
  5. Univ. of Colorado, Boulder, CO (United States)
  6. Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
  7. Univ. del Pais Vasco, San Sebastian (Spain); Donostia International Physics Center, San Sebastian (Spain)
  8. Univ. de Cantabria, Santander (Spain)
  9. Luxembourg Institute of Science and Technology (LIST), Esch/Alzette (Luxembourg)
Publication Date:
Grant/Contract Number:
Accepted Manuscript
Journal Name:
Nature Materials
Additional Journal Information:
Journal Volume: 16; Journal Issue: 10; Journal ID: ISSN 1476-1122
Nature Publishing Group
Research Org:
Argonne National Lab. (ANL), Argonne, IL (United States)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22), Materials Sciences and Engineering Division; U.S. Army Research Laboratory, U.S. Army Research Office (ARO); National Science Foundation (NSF); Swiss National Science Foundation (SNSF); Spanish Ministerio de Economia y Competitividad (MINECO); Gordon and Betty Moore Foundation
Country of Publication:
United States
OSTI Identifier: