First-principles study of the ferrielectric of X-doped KNbO3 (X = Na, Rb, and Cs)

Abstract

Perovskite ferroelectrics has great value and many new structures have been synthesized experimentally by doping with new components. But there were few studies on single atom substitution in theory. This article investigates the ferroelectricity of KNbO3 when some of the K atoms are replaced with elements of the same main group. Structural, polarization and electronic of different type KNbO3 were calculated using first principles calculations. Analysis of relaxed structure and electron charge shows that the different atom substitution produces different distortion. The combined analysis leads to the conclusion that the ferroelectricity decreases with increasing radius of the homologous atoms. This provides an explanation for the experimental data from another perspective.