SXRD Charge Density of KNbO₃ Ferroelectric Perovskite

Abstract

The electrostatic potential distributions of KNbO₃ ferroelectric perovskite are experimentally evaluated by analyzing synchrotron radiation X-ray powder diffraction (SXRD) data using the Rietveld method and the maximum entropy method. The electric field distribution calculated by taking the gradient of the electrostatic potential distribution in the polar direction reveals the emergence of electronic polarization arising from the anisotropic covalent bonding on the Nb-O bonds. The SXRD electron charge density studies demonstrate that the K ion makes little contribution to the electronic polarization in all ferroelectric phases of KNbO₃.

Keywords:

• KNbO₃
• spontaneous polarization
• electronic polarization
• electron charge density
• electrostatic potential
• powder diffraction
• synchrotron radiation
• maximum entropy method