Microscopic picture of paraelectric perovskites from structural prototypes

Abstract

We show with first-principles molecular dynamics the persistence of intrinsic $⟨111⟩$ Ti off-centerings for BaTiO${}_3$ in its cubic paraelectric phase. Intriguingly, these are inconsistent with the Pm$\bar{3}$m space group often used to atomistically model this phase using density functional theory or similar methods. Therefore we deploy a systematic symmetry analysis to construct representative structural models in the form of supercells that satisfy a desired point symmetry but are built from the combination of lower-symmetry primitive cells. We define as structural prototypes the smallest of these that are both energetically and dynamically stable. Remarkably, two 40-atom prototypes can be identified for paraelectric BaTiO${}_3$; these are also common to many other $AB$O${}_3$ perovskites. These prototypes can offer structural models of paraelectric phases that can be used for the computational engineering of functional materials. Last, we show that the emergence of B-cation off-centerings and the primitive-cell phonon instabilities are controlled by the equilibrium volume, in turn dictated by the filler A cation.

18 pages, 4 figures in main text, 14 figures in appendix

References in corpus (10)

• Quantum ESPRESSO: a modular and open-source software project for quantum simulations of materials
• Restoring the density-gradient expansion for exchange in solids and surfaces
• Generalized gradient approximation for solids and their surfaces
• Advanced capabilities for materials modelling with Quantum ESPRESSO
• Origin of band gaps in 3d perovskite oxides
• A polymorphous band structure model of gapping in the anti-ferromagnetic and paramagnetic phases of the Mott insulators MnO, FeO, CoO, and NiO
• Uncovering and tailoring hidden Rashba spin-orbit splitting in centrosymmetric crystals
• Hidden, entangled and resonating order
• Microscopic picture of paraelectric perovskites from structural prototypes
• Gate control of spin-layer-locking FETs and application to monolayer LuIO

Cited by in corpus (8)

• Thermodynamics and dielectric response of ${\text{BaTiO}}_3$ by data-driven modeling
• Intrinsic local symmetry-breaking in nominally cubic paraelectric BaTiO3
• First-principles thermodynamics of CsSnI3
• Understanding the role of Hubbard corrections in the rhombohedral phase of BaTiO${}_3$
• Microscopic picture of paraelectric perovskites from structural prototypes
• Real Space Visualization of Order-Disorder Transition in BaTiO3
• The thermodynamics of CaSiO3 in Earth's lower mantle
• Ab initio functional-independent calculations of the clamped Pockels tensor of tetragonal barium titanate