On the origin of supertetragonality in BaTiO${}_3$

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 $\sim 1.3$. 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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Cited by in corpus (2)

• Understanding the role of Hubbard corrections in the rhombohedral phase of BaTiO${}_3$
• Confinement-Induced Isosymmetric Metal-Insulator Transition in Ultrathin Epitaxial V2O3 Films