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This content will become publicly available on September 22, 2017

Title: Three-mode coupling interference patterns in the dynamic structure factor of a relaxor ferroelectric

A long-standing controversy for relaxor ferroelectrics has been the origin of the waterfall effect in the phonon dispersion curves, in which low-energy transverse phonons cascade into vertical columns. Originally interpreted as phonons interacting with polar nanoregions (PNRs), it was later explained as an interference effect of coupling damped optic and acoustic phonons. In light of a recently discovered PNR vibrational mode near the waterfall wavevector [M. E. Manley, J. W. Lynn, D. L. Abernathy, E. D. Specht, O. Delaire, A. R. Bishop, R. Sahul, and J. D. Budai, Nat. Commun. 5, 3683 (2014)] we have reexamined this feature using neutron scattering on [100]-poled PMN-30%PT (0.6Pb(Mg1/3Nb2/3)O3 0.3PbTiO3). In addition, we find that the PNR mode couples to both optic and acoustic phonons, and that this results in complex patterns in the dynamic structure factor, including intensity pockets and peaks localized in momentum-energy space. These features are fully explained by extending the mode-coupling model to include three coupled damped harmonic oscillators representing the transverse optic, acoustic, and PNR modes.
Authors:
 [1] ;  [1] ;  [2] ;  [1] ;  [1]
  1. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
  2. TRS Technologies, State College, PA (United States)
Publication Date:
OSTI Identifier:
1326524
Grant/Contract Number:
AC05-00OR22725
Type:
Accepted Manuscript
Journal Name:
Physical Review B
Additional Journal Information:
Journal Volume: 94; Journal Issue: 10; Journal ID: ISSN 2469-9950
Publisher:
American Physical Society (APS)
Research Org:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Spallation Neutron Source (SNS)
Sponsoring Org:
USDOE Office of Science (SC)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY