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Abstract Processing–structure relationships are at the heart of materials science, and predictive tools are essential for modern technological industries insofar as structure dictates intrinsic properties; however, few theoretical models exist for cation‐ordered perovskites. In this work, a combination of data mining and solid‐state synthesis was employed to collect structural data of 1:2 ordered (triple) perovskites. Three compositions within the (Ba1 − xSrx)(Mg1/3Ta2/3)O3system were synthesized using a conventional solid‐state mixed‐oxide method. X‐ray diffraction data showed evidence of long‐range 1:2 B‐site cation ordering for all compositions. Additional data for another 24 1:2 ordered compositions were mined from literature. Correlative models for the deviation in modified tolerance factor (Δt′) were derived for each system, and a general model which is capable of predicting the pseudocubic lattice constants of such perovskites based solely on published ionic‐radii data developed.
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Anion order in oxysulfide perovskites: origins and implications
Abstract Heteroanionic oxysulfide perovskite compounds represent an emerging class of new materials allowing for a wide range of tunability in the electronic structure that could lead to a diverse spectrum of novel and improved functionalities. Unlike cation ordered double perovskites—where the origins and design rules of various experimentally observed cation orderings are well known and understood—anion ordering in heteroanionic perovskites remains a largely uncharted territory. In this contribution, we present and discuss insights that have emerged from our first-principles-based electronic structure analysis of a prototypical anion-ordered SrHf(O0.5S0.5)3oxysulfide chemistry, studied in all possible anion configurations allowed within a finite size supercell. We demonstrate that the preferred anion ordering is always an all-cisarrangement of anions around an HfO3S3octahedron. As a general finding beyond the specific chemistry, the origins of this ordering tendency are traced back to a combined stabilization effect stemming from electronic, elastic, and electrostatic contributions. These qualitative notions are also quantified using state-of-the-art machine learning models. We further study the relative stability of the identified ordering as a function of A (Ca, Sr, Ba) and B (Ti, Zr, Hf) site chemistries and probe chemistry-dependent trends in the electronic structure and functionality of the material. Most remarkably, we find that the identified ground-state anion ordering breaks the inversion symmetry to create a family of oxysulfide ferroelectrics with a macroscopic polarization >30 μC/cm2, exhibiting a significant promise for electronic materials applications.
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- Award ID(s):
- 1806147
- PAR ID:
- 10158369
- Publisher / Repository:
- Nature Publishing Group
- Date Published:
- Journal Name:
- npj Computational Materials
- Volume:
- 6
- Issue:
- 1
- ISSN:
- 2057-3960
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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