@article{33373,
  keywords = {Temperature, Electric fields, Polarization, Ferroelectricity, Ferroelectric domains, Vortex flow, Electric-field control, First-order phase transitions, Oxide superlattices, Condensed matter physics, Characterization techniques, Ferroelectric phasis, Nonlinear optical response, Superlattice periods},
  author = {A.R Damodaran and J.D Clarkson and Z Hong and H B Liu and A.K Yadav and C.T Nelson and S.-L Hsu and M.R McCarter and K.-D Park and V Kravtsov and A Farhan and Y Dong and Z Cai and H Zhou and P Aguado-Puente and P García-Fernández and J Íñiguez and J Junquera and A Scholl and M.B Raschke and L.-Q Chen and D.D Fong and Ramamoorthy Ramesh and L.W Martin},
  title = {Phase coexistence and electric-field control of toroidal order in oxide superlattices},
  abstract = {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. Our findings suggest new cross-coupled functionalities. © 2017 Macmillan Publishers Limited, part of Springer Nature. All rights reserved.},
  year = {2017},
  journal = {Nature Materials},
  volume = {16},
  number = {10},
  pages = {1003-1009},
  publisher = {Nature Publishing Group},
  issn = {14761122},
  doi = {10.1038/NMAT4951},
  note = {cited By 50},
  language = {eng},
}