Project 24-11275S of the Czech Science Foundation:
Computational design of high-performance ferroelectrics (2024-2026)
Modern dielectric materials with exceptional electromechanical response are based on perovskite solid solutions
in the composition range of the morphotropic phase boundary (MPB). Despite their importance for applications,
the explanation of their performance is elusive, as it is hard to access the real short-range atomic order experimentally and
accurate calculations of finite-temperature properties with current models are challenging.
We propose a comprehensive approach combining multiscale modeling and experiment.
We engage first-principle techniques to design interatomic potentials fine-tuned for the atomic order in MPBs,
which will be determined experimentally using the recently developed anomalous diffuse scattering method.
Molecular-dynamics simulations of large enough structures will provide direct insight into the local structure-property relationship.
Potentials for various cation species will enable to develop a high-throughput screening scheme and design of new,
environmentally-friendly materials. The best candidates will be synthesized and characterized.
Project 19-28594X of the Czech Science Foundation:
Ferroelectric skyrmions (2019-2023)
Domain walls in ferroelectrics are naturally formed 2D solitons with a defined, nm-thick polarization profile
stable over macroscopic lateral dimensions. Strong coupling of the polarization gradient
with strain drastically changes the material properties within the domain wall thickness.
Increasing attention is paid to these mobile interfaces because the characterization tools have recently reached
the desired nanoscale resolution, needed to uncover the rich spectrum of new phenomena expected there.
We are convinced that some ferroelectrics can also host 1D analogues of domain walls,
i.e. spontaneously formed ferroelectric line solitons, similar to the recently experimentally confirmed
Bogdanov-Yablonskitype magnetic skyrmion lines. We wish to extend the explorations also
to these interesting topological objects and to pave a path to the experimental discovery of the ferroelectric skyrmion phases,
analogous to the vortex states in superconductors and skyrmion phases of chiral magnets.
GACR 15-04121S: Emergent perspectives of ferroelectric interfaces (2015-2017)
The project focuses on investigation of the structure and properties of ideal two-dimensional
nanoscale objects: domain walls and similar interfaces in modern ferroelectric materials.
The research will be targeted to explore the nature and application potential of three recently reported discoveries:
(i) ferroelectric photovoltaic effect on domain walls of bismuth ferrite,
(ii) exotic chiral domain wall species in rhombohedral barium titanate and
(iii) giant softening of elastic constants of relaxor ferroelectrics.
GACR P204/10/0616: Modern piezoelectric perovskites: lattice vibrations and domain walls (2010-2012)
The main goal of this project is to achieve a deeper understanding of the mechanisms leading to high
permittivity and piezoelectricity in modern perovskite-type materials. For this purpose we will use a range of
spectroscopic techniques and closely related theoretical first-principles and phenomenological calculations. In
particular, we expect to get insight in typical domain structures of these materials by employing apparatus
allowing simultaneous recording of local Raman and piezoelectric response using the recently available
combination of micro-Raman and atomic force microscope scanning techniques. Bulk spectroscopic
experiments will be used to refine the material-specific Ginzburg-Landau-Devonshire models needed
to quantify the role of the identified nanodomain arrangements in the macroscopic piezoelectric response.
GACR 202-06-0411: Domain phenomena in ferroic crystals (2006-2008)
Main aim of the proposed project is the study of domain
structures in crystals belonging to the various
ferroelectric species (BaTiO3, KNbO3, LiTaO3, LiNbO3, Pb5Ge3O11 etc.). Technically, the subject is approached by applying domain engineering techniques, phenomenological modelling, optical microscopy, piezoelectric measurements, as well as structural and spectroscopic investigations.
The final application target is enhancement of the piezoelectric coefficients due to the domain
engineering in crystals with defined
multi-domain structures. Second possible goal is to demonstrate tuning of the resonant
frequency temperature dependence for piezoelectric resonators with
multi-domain structure.
Last update 14/11/2016 by
