Bi-O covalency in PbTiO3-BiInO3 with enhanced ferroelectric properties: Synchrotron radiation diffraction and first-principles study

Abstract

High-TC ferroelectric (1 − x)PbTiO3-xBiInO3 shows a sustainable spontaneous polarization in tetragonal phase by amount of BiInO3 augmented. It is rare and interesting that weak ferroelectric In3+ substitution does not reduce ferroelectricity as most of BiMeO3 materials. To understand this abnormality behavior, the structure and the cation displacements are studied by means of synchrotron radiation diffraction. The cation displacements of A-site atoms and B-site atoms exhibit a coupling property. Their sustainedly increasing trend is quantitatively associated with spontaneous polarization. Moreover, the structure, the valence electron density distributions, electron localization function, and Bader analysis have been researched on the chemical bond in (1 − x)PbTiO3-xBiInO3 through first-principles calculations here. Although In atoms substitution reduces the covalency degree, this loss is offset by enhanced covalency between Bi-O bonds. The crucial role of Bi atom substitution not only contributes to enhance the covalency but also promotes the polarization.

Combined theoretical and nanoscale experimental study of Pb(Ca,Ba)TiO3, Pb(Sr,Ba)TiO3, and Pb(Sr,Ca)TiO3 complex perovskite structures: An investigation of the ferroelectric and electronic properties

“…In addition, examining the PbTiO 3 partial DOS in detail, the top of the valence band contains stronger admixtures of Pb s and O p orbitals in comparison to PCBT-60, PSBT-60, and PSCT-60 partial DOS; this represents a stronger PbeO covalency, which in turn stabilizes the larger ferroelectric tetragonal phase in the PbTiO 3 prototype. This observation is consistent with many simulation results reported in the literature [34,35]. From the calculated DOS for PCBT-60, PSBT-60, and PSCT-60 electronic structures, it can be observed that for all three compounds the VB is predominantly composed of O p states, whereas Ti d states contribute predominantly to the CB, as seen Fig.…”

High piezoelectricity with broad temperature insensitivity in BiScO3–PbTiO3‐based piezoceramics

“…The short‐range disorder dominates in the end. In BS– x BPZnT ceramics, Pb ions at the A‐sites are replaced by Bi ions, which increases the A–O ion hybridization 25 and affects the substitution of B‐site ions (Ti 4+ , Sc 3+ , Zn 2+ ). The Zn‐replaced Ti simultaneously generates O vacancies for electric neutrality.…”

Supertetragonal Phases of Perovskite Oxides: Insights from Electronic Structure Calculations

“…However, the case of M = In is particularly unusual, since In 3 + ions are weak ferroelectric ions. In the work of Wang and collaborators, [52] they calculated the valence electron density distribution, using density-functional theory, and found that the bismuth-substitution in BiInO 3 À PbTiO 3 systems promotes the covalency between the A-site cations and oxygen atoms, whereas the indium-substitution demotes the covalency between the B-site cations and oxygen atoms. Further calculations of the electron localization function and Bader analysis confirmed that the atomic Bader charges are significantly smaller than the formal ionic charges.…”