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

TYC@UCL member Warda Rahim recently worked with a team of researchers and published her results in Chemical Science. In this work, she presents a computational method to identify and characterise stable polymorphs and phase transitions in materials with complex crystal structures.

Accurate modelling of polymorphism in crystalline solids is one of the main challenges in computational chemistry and materials science. In this work, we used first-principles lattice dynamics calculations, involving phonon calculations and mapping of imaginary frequency modes, to understand polymorphism in the complex metal oxide Bi2Sn2O7. The method successfully recovers the known experimental phases and also identifies 3 new metastable phases on the potential energy surface. The approach presented is completely general and provides a practical means to characterise phase transitions in materials with complex crystal structures.

Warda Rahim, Jonathan M. Skelton, Christopher N. Savory, Ivana R. Evans, John S. O. Evans, Aron Walsh and David O. Scanlon

https://pubs.rsc.org/en/content/articlelanding/2020/sc/d0sc02995e#!divAbstract

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