title: Thermal Fluctuations of Ferroelectric Nanodomains in a Ferroelectric-Dielectric PbTiO_{3}/SrTiO_{3} Superlattice.
abstract: Ferroelectric-dielectric superlattices consisting of alternating layers of ferroelectric PbTiO_{3} and dielectric SrTiO_{3} exhibit a disordered striped nanodomain pattern, with characteristic length scales of 6 nm for the domain periodicity and 30 nm for the in-plane coherence of the domain pattern. Spatial disorder in the domain pattern gives rise to coherent hard x-ray scattering patterns exhibiting intensity speckles. We show here using variable-temperature Bragg-geometry x-ray photon correlation spectroscopy that x-ray scattering patterns from the disordered domains exhibit a continuous temporal decorrelation due to spontaneous domain fluctuations. The temporal decorrelation can be described using a compressed exponential function, consistent with what has been observed in other systems with arrested dynamics. The fluctuation speeds up at higher temperatures and the thermal activation energy estimated from the Arrhenius model is 0.35±0.21  eV. The magnitude of the energy barrier implies that the complicated energy landscape of the domain structures is induced by pinning mechanisms and domain patterns fluctuate via the generation and annihilation of topological defects similar to soft materials such as block copolymers.
authors.affiliation: X-Ray Science Division, Argonne National Laboratory, Lemont, Illinois 60439, USA.
authors.forename: Qingteng
authors.initials: Q
authors.lastname: Zhang
authors.affiliation: X-Ray Science Division, Argonne National Laboratory, Lemont, Illinois 60439, USA.
authors.forename: Eric M
authors.initials: EM
authors.lastname: Dufresne
authors.affiliation: X-Ray Science Division, Argonne National Laboratory, Lemont, Illinois 60439, USA.
authors.forename: Pice
authors.initials: P
authors.lastname: Chen
authors.affiliation: Department of Materials Science and Engineering, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA.
authors.forename: Joonkyu
authors.initials: J
authors.lastname: Park
authors.affiliation: Department of Materials Science and Engineering, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA.
authors.forename: Margaret P
authors.initials: MP
authors.lastname: Cosgriff
authors.affiliation: Department of Physics and Astronomy, Stony Brook University, Stony Brook, New York 11794, USA.
authors.forename: Mohammed
authors.initials: M
authors.lastname: Yusuf
authors.affiliation: Materials Science Division, Argonne National Laboratory, Lemont, Illinois 60439, USA.|National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei, Anhui 230026, China.
authors.forename: Yongqi
authors.initials: Y
authors.lastname: Dong
authors.affiliation: Materials Science Division, Argonne National Laboratory, Lemont, Illinois 60439, USA.
authors.forename: Dillon D
authors.initials: DD
authors.lastname: Fong
authors.affiliation: X-Ray Science Division, Argonne National Laboratory, Lemont, Illinois 60439, USA.
authors.forename: Hua
authors.initials: H
authors.lastname: Zhou
authors.affiliation: X-Ray Science Division, Argonne National Laboratory, Lemont, Illinois 60439, USA.
authors.forename: Zhonghou
authors.initials: Z
authors.lastname: Cai
authors.affiliation: X-Ray Science Division, Argonne National Laboratory, Lemont, Illinois 60439, USA.
authors.forename: Ross J
authors.initials: RJ
authors.lastname: Harder
authors.affiliation: Department of Physics and Astronomy, Stony Brook University, Stony Brook, New York 11794, USA.
authors.forename: Sara J
authors.initials: SJ
authors.lastname: Callori
authors.affiliation: Department of Physics and Astronomy, Stony Brook University, Stony Brook, New York 11794, USA.
authors.forename: Matthew
authors.initials: M
authors.lastname: Dawber
authors.affiliation: Department of Materials Science and Engineering, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA.
authors.forename: Paul G
authors.initials: PG
authors.lastname: Evans
authors.affiliation: X-Ray Science Division, Argonne National Laboratory, Lemont, Illinois 60439, USA.
authors.forename: Alec R
authors.initials: AR
authors.lastname: Sandy