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arXiv · 2201.07569

On the origin of supertetragonality in BaTiO$_3$

Simon Mellaerts·Jin Won Seo·Valeri Afanas'ev·Michel Houssa·Jean-Pierre Locquet
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Abstract

Understanding ferroelectricity is of both fundamental and technological importance to further stimulate the development of new materials designs and manipulations. Here, we perform an in-depth first-principle study on the well-known ferroelectric barium titanate BaTiO$_{3}$ under a hydrostatic negative pressure, showing an isosymmetric phase transition to a supertetragonal phase with high $c/a$ ratio of $\sim1.3$. The microscopic origin and driving mechanisms of this phase transition are identified as a drastic change of the covalently $\pi$-bonded electrons. These findings provide guidance in the search for new supertetragonal phases, with great opportunities for novel multiferroic materials; and can be generalized in the understanding of other isosymmetric phase transitions.

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Simon Mellaerts, Jin Won Seo, Valeri Afanas'ev, Michel Houssa, Jean-Pierre Locquet. 2022-01-19. On the origin of supertetragonality in BaTiO$_3$. https://doi.org/10.1103/physrevmaterials.6.064410

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