Temperature dependent Raman spectroscopic study of Fano resonance in perovskite ferroelectric KTa 1-x Nb x O 3 single crystal

Abstract

Fano resonance arises from the interference of a localized discrete state coupled to the continuum states, which has become an indispensable probe in physical and chemical sciences. Compared with plenty of studies in the artificial meta-structures, Fano resonances in single crystals were rarely reported. Herein, we performed a comprehensive study on Fano resonances of KTa 1-x Nb x O 3 (KTN) ferroelectric single crystals using temperature dependent Raman spectroscopy. The Fano asymmetric q factors were fitted for KTN crystals with various Nb concentrations. We found that the q factors were strongly correlated to Curie temperature T c and ferroelectric polarization arrangement in different phase regions. In addition, the regulation of dopant transition metals on the Fano effect was also investigated in Cu:KTN and Fe:KTN crystals.