Role of Electron–Phonon Interaction in Phase Transition of Zr-Substituted BaTiO3

Abstract

The tetragonal to cubic phase transition in BaTiO₃ is a critical phenomenon, as it marks the ferroelectric to paraelectric transition. This study investigates the effects of zirconium substitution on the vibrational mode and phase transition behavior of BaTiO₃ crystal lattice through Raman spectroscopy. A series of Ba(Ti,Zr)O₃ compositions were analyzed and the results indicate that Zr substitutions alter the phonon dynamics and reduce the Ti-site distortion. The Raman spectra of Ba(Ti,Zr)O₃ compositions display distinctive features that correlate with the progression of the phase transition, highlighting the sensitivity of this technique to dopant-driven modifications of the local structure. Thus, this work highlights the potential of Raman spectroscopy as a powerful tool for probing structural transformations and provides a new understanding of the role of electron–phonon coupling-driven phase transition in Zr-substituted BaTiO₃. The results are supported by the theoretical Fano formulation and calculation of Helmholtz free energy for Zr-substituted BaTiO₃.