Electronic polarization in KNbO3 visualized by synchrotron radiation powder diffraction

Shoto Kawamura, Eisuke Magome, Chikako Moriyoshi, Yoshihiro Kuroiwa, Nao Taniguchi, Hiroshi Tanaka, Sachiko Maki, Masaki Takata, Satoshi Wada

Research output: Contribution to journalArticlepeer-review

4 Citations (Scopus)

Abstract

Electron charge density studies of a potassium niobate KNbO3 perovskite-type crystal have been carried out by analyzing synchrotron radiation X-ray powder diffraction data using a combination of the Rietveld method and the maximum entropy method. The crystal structures of the cubic, tetragonal, orthorhombic, and rhombohedral phases are accurately analyzed associated with the successive ferroelectric phase transitions by taking the multicomponent structures in the ferroelectric phases into account. The electrostatic potential analyses reveal the emergence of electronic polarization arising from the anisotropic covalent bonding on the Nb and O atoms, while no significant electronic polarization is detected on the isolated K ion. Thus, the spontaneous polarization is caused by the ionic displacements of the constituent atoms and the imbalance of the hybrid atomic orbitals on the Nb-O bonding.

Original languageEnglish
Article number09KF04
JournalJapanese journal of applied physics
Volume52
Issue number9 PART2
DOIs
Publication statusPublished - 2013 Sep
Externally publishedYes

ASJC Scopus subject areas

  • Engineering(all)
  • Physics and Astronomy(all)

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