Phase transition mechanism in KIO3 single crystals

Abstract

Detailed polarized Raman study was performed on KIO3 single crystals over 78.5-553K, which show a strong central component in the high temperature phase I and two soft modes S1 and S2 related to the phase transitions I-II and II-III respectively. The phonon dispersion of KIO3 in phase I was calculated, utilizing density functional perturbation theory (DFPT) and local density approximation (LDA). The KIO 3 single crystals were ascribed to improper ferroelectrics with the phase transition series from rhombohedral phase I, to monoclinic phase II, to triclinic phase III, and phase IV. © 2006 IOP Publishing Ltd.