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Title: Emergent Low-Symmetry Phases and Large Property Enhancements in Ferroelectric KNbO 3 Bulk Crystals

Abstract

The design of new or enhanced functionality in materials is traditionally viewed as requiring the discovery of new chemical compositions through synthesis. Large property enhancements may however also be hidden within already well-known materials, when their structural symmetry is deviated from equilibrium through a small local strain or field. Here, the discovery of enhanced material properties associated with a new metastable phase of monoclinic symmetry within bulk KNbO3 is reported. This phase is found to coexist with the nominal orthorhombic phase at room temperature, and is both induced by and stabilized with local strains generated by a network of ferroelectric domain walls. While the local microstructural shear strain involved is only approximate to 0.017%, the concurrent symmetry reduction results in an optical second harmonic generation response that is over 550% higher at room temperature. Moreover, the meandering walls of the low-symmetry domains also exhibit enhanced electrical conductivity on the order of 1 S m(-1). This discovery reveals a potential new route to local engineering of significant property enhancements and conductivity through symmetry lowering in ferroelectric crystals.

Authors:
 [1];  [1];  [2];  [3];  [3];  [1];  [1];  [4];  [3];  [5];  [1]
  1. Department of Materials Science and Engineering, Pennsylvania State University, University Park, PA 16802 USA
  2. School of Mathematics and Physics, Queen's University Belfast, University Road, Belfast BT71NN Northern Ireland UK
  3. Department of Physics, University of Texas at Austin, Austin TX 78712 USA
  4. Center for Nanoscale Materials, Argonne National Laboratory, Argonne IL 60439 USA
  5. Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge TN 37831 USA
Publication Date:
Research Org.:
Argonne National Lab. (ANL), Argonne, IL (United States)
Sponsoring Org.:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
OSTI Identifier:
1389316
DOE Contract Number:
AC02-06CH11357
Resource Type:
Journal Article
Resource Relation:
Journal Name: Advanced Materials; Journal Volume: 29; Journal Issue: 31
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE

Citation Formats

Lummen, Tom T. A., Leung, J., Kumar, Amit, Wu, X., Ren, Y., VanLeeuwen, Brian K., Haislmaier, Ryan C., Holt, Martin, Lai, Keji, Kalinin, Sergei V., and Gopalan, Venkatraman. Emergent Low-Symmetry Phases and Large Property Enhancements in Ferroelectric KNbO 3 Bulk Crystals. United States: N. p., 2017. Web. doi:10.1002/adma.201700530.
Lummen, Tom T. A., Leung, J., Kumar, Amit, Wu, X., Ren, Y., VanLeeuwen, Brian K., Haislmaier, Ryan C., Holt, Martin, Lai, Keji, Kalinin, Sergei V., & Gopalan, Venkatraman. Emergent Low-Symmetry Phases and Large Property Enhancements in Ferroelectric KNbO 3 Bulk Crystals. United States. doi:10.1002/adma.201700530.
Lummen, Tom T. A., Leung, J., Kumar, Amit, Wu, X., Ren, Y., VanLeeuwen, Brian K., Haislmaier, Ryan C., Holt, Martin, Lai, Keji, Kalinin, Sergei V., and Gopalan, Venkatraman. Mon . "Emergent Low-Symmetry Phases and Large Property Enhancements in Ferroelectric KNbO 3 Bulk Crystals". United States. doi:10.1002/adma.201700530.
@article{osti_1389316,
title = {Emergent Low-Symmetry Phases and Large Property Enhancements in Ferroelectric KNbO 3 Bulk Crystals},
author = {Lummen, Tom T. A. and Leung, J. and Kumar, Amit and Wu, X. and Ren, Y. and VanLeeuwen, Brian K. and Haislmaier, Ryan C. and Holt, Martin and Lai, Keji and Kalinin, Sergei V. and Gopalan, Venkatraman},
abstractNote = {The design of new or enhanced functionality in materials is traditionally viewed as requiring the discovery of new chemical compositions through synthesis. Large property enhancements may however also be hidden within already well-known materials, when their structural symmetry is deviated from equilibrium through a small local strain or field. Here, the discovery of enhanced material properties associated with a new metastable phase of monoclinic symmetry within bulk KNbO3 is reported. This phase is found to coexist with the nominal orthorhombic phase at room temperature, and is both induced by and stabilized with local strains generated by a network of ferroelectric domain walls. While the local microstructural shear strain involved is only approximate to 0.017%, the concurrent symmetry reduction results in an optical second harmonic generation response that is over 550% higher at room temperature. Moreover, the meandering walls of the low-symmetry domains also exhibit enhanced electrical conductivity on the order of 1 S m(-1). This discovery reveals a potential new route to local engineering of significant property enhancements and conductivity through symmetry lowering in ferroelectric crystals.},
doi = {10.1002/adma.201700530},
journal = {Advanced Materials},
number = 31,
volume = 29,
place = {United States},
year = {Mon Jun 19 00:00:00 EDT 2017},
month = {Mon Jun 19 00:00:00 EDT 2017}
}