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Department of Dielectrics

Institute of Physics of the Czech Academy of Sciences


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Topological structures

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Antiskyrmions in ferroelectric barium titanate

Our recent molecular dynamics computational study reveals that the bulk crystal of the archetypal ferroelectric perovskite BaTiO3 can host ferroelectric antiskyrmions at zero field. We show that the antiskyrmion has just 2-3 nm in diameter and that it carries a very exotic topological charge of minus two [Phys. Rev. Lett. 133, 066802 (2024)].

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Zigzag charged domain walls in ferroelectric PbTiO3

We report a theoretical investigation of a charged 180-degree domain wall in ferroelectric PbTiO3, compensated by randomly distributed immobile charge defects. We predict that domain walls form a zigzag pattern and we discuss their properties in a broad interval of compensation-region widths. The zigzag is accompanied by a local polarization rotation which we explain to provide an efficient mechanism for charge compensation [Phys. Rev. B 107, 094102 (2023)].

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Multidomain ordered metal–ferroelectric superlattices

By combination of advanced experimental techniques and phase-field simulations, we found that electric dipoles in superlattices, composed of layers of a ferroelectric material separated by thin metallic spacers, form an unusual pattern of nanoscale domains that order in three dimensions. These ferroelectric multidomain ordered superlattices exhibit an outstanding dielectric response and their engineered modulated structural and electronic properties can be controlled using electric field [Nat. Mater. 20, 495 (2021)].

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Existence conditions for ferroaxial materials

All 212 species of structural phase transitions with a macroscopic symmetry breaking were inspected with respect to the simultaneous occurrence of the ferroelastic, ferroelectric, and ferroaxial properties.

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Ising lines: Natural topological defects within ferroelectric Bloch walls

Phase-field simulations demonstrate that the polarization order-parameter field in the Ginzburg-Landau-Devonshire model of rhombohedral ferroelectric BaTiO3 allows for an interesting linear defect, stable under simple periodic boundary conditions. This linear defect, here called the Ising line, can be described as an about 2-nm-thick intrinsic paraelectric nanorod acting as a highly mobile borderline between finite portions of Bloch-like domain walls of opposite helicity.

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Phase transition in ferroelectric domain walls of BaTiO3

The seminal paper by Zhirnov (1958 Zh. Eksp. Teor. Fiz. 35 1175–80) explained why the structure of domain walls in ferroelectrics and ferromagnets is so different. We have recently realized that the antiparallel ferroelectric walls in rhombohedral ferroelectric BaTiO3 can be switched between the Ising-like state (typical for ferroelectrics) and a Bloch-like state (unusual for ferroelectric walls but typical for magnetic ones) [see Figure 1] by a compressive epitaxial stress.

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Dielectric response of a phase transition in domain wall

Computer simulations based on Ginzburg-Landau-Devonshire theory was used to study details of a phase-transition between Ising and Bloch type of a domain wall.

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Piezoelectric response of nanotwinned ferroelectric perovskites

Computer simulations based on Ginzburg-Landau-Devonshire theory has benn used to investigate piezoelectric properties of tetragonal BaTiO3 crystals. We have shown that piezoelectric response of twinned BaTiO3 increases with increasing density of 90-degree domain walls.

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