Polymorph exploration of bismuth stannate using first-principles phonon mode mapping

Accurately modelling polymorphism in crystalline solids remains a key challenge in computational chemistry. In this work, we apply a theoretically-rigorous phonon mode-mapping approach to understand the polymorphism in the ternary metal oxide Bi 2 Sn 2 O 7 . Starting from the high-temperature cubic...

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Bibliographic Details
Published in:Chemical science (Cambridge) 2020-08, Vol.11 (3), p.794-799
Main Authors: Rahim, Warda, Skelton, Jonathan M, Savory, Christopher N, Evans, Ivana R, Evans, John S. O, Walsh, Aron, Scanlon, David O
Format: Article
Language:English
Subjects:
Bismuth
Chemistry
Computational chemistry
Crystal structure
First principles
High temperature
Low temperature
Mapping
Metal oxides
Metastable phases
Phase transitions
Phonons
Polymorphism
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Summary:Accurately modelling polymorphism in crystalline solids remains a key challenge in computational chemistry. In this work, we apply a theoretically-rigorous phonon mode-mapping approach to understand the polymorphism in the ternary metal oxide Bi 2 Sn 2 O 7 . Starting from the high-temperature cubic pyrochlore aristotype, we systematically explore the structural potential-energy surface and recover the two known low-temperature phases alongside three new metastable phases, together with the transition pathways connecting them. This first-principles lattice-dynamics method is completely general and provides a practical means to identify and characterise the stable polymorphs and phase transitions in materials with complex crystal structures. Using a phonon mode-mapping approach, we recover the known experimental phases of the ternary oxide Bi 2 Sn 2 O 7 and identify three new metastable phases, highlighting the utility of the method for polymorph prediction on many other complex materials.
ISSN:2041-6520
2041-6539
DOI:10.1039/d0sc02995e