Related papers: Dynamic Local Distortions in Ferroelectrics
In this work, we report a massively parallel and time domain implementation of the 3D phase field model that can reach beyond micron scale and consider for arbitrary electrical and mechanical boundary conditions. The first part of the paper…
We study from first-principles calculations the ferroelectric structural phase transition of Pb$_5$Ge$_3$O$_{11}$ crystal. The calculations of phonons and Born effective charges of the paraelectric phase allow us to identify a polar…
We investigate the phase diagrams of RMn$_2$O$_5$ via a first-principles effective-Hamiltonian method. We are able to reproduce the most important features of the complicated magnetic and ferroelectric phase transitions. The calculated…
Pb-based perovskites with multiple cations are fascinating materials showing various phenomena such as high piezoelectric, electromechanical, and relaxor properties. While chemical disordering accompanied by polar nanoregions and nanosized…
Surprisingly little is known about the microscopic processes that govern ferroelectric switching in orthorhombic ferroelectrics. To study microscopic switching processes we combine ab initio-based molecular dynamics simulations and data…
Using first-principles calculations, the phonon frequencies at the $\Gamma$ point and the dielectric tensor are determined and analysed for the cubic and rhombohedral phases of BaTiO$_{3}$. The dipole-dipole interaction is then separated…
We analyze a system of polar molecules in a one-dimensional optical lattice. By controlling the internal structure of the polar molecules with static electric and microwave fields, we demonstrate the appearance of a quantum phase transition…
The equilibrium ground-state structure of LiNbO3 in the paraelectric and ferroelectric phases is fully optimized in a first-principles calculation using the full-potential linearized augmented plane wave method. The equilibrium volume, c/a…
The Landau theory of phase transitions has been re-examined under the framework of a modified mean field theory in ferroelectrics. By doing so, one can see that there are two atomic movements involved in the ferroelectric phase transition;…
The phonon dispersion curves of cubic BaTiO_3 have been computed within a first-principles approach and the results compared to the experimental data. The curves obtained are very similar to those reported for KNbO_3 by Yu and Krakauer…
Ferroelectric and multiferroic materials form an important class of functional materials. Over the last twenty years, first-principles-based effective Hamiltonian approaches have been successfully developed to simulate these materials. In…
To investigate the possible origin and mechanism of ferroelectricity in polycrystalline spin ices Ho2Ti2O7 and Dy2Ti2O7 a detailed dielectric study has been performed. Experimental finding suggests that both materials have two prominent…
We show how microstructure can arise in first-order ferroelastic structural transitions, in two and three spatial dimensions, through a local meanfield approximation of their pseudospin hamiltonians, that include anisotropic elastic…
Electronic correlations beyond static mean-field theories are of fundamental importance in describing the properties of complex materials - such as transition-metal oxides - where the low-energy physics is driven by localized d or f…
We investigate the quantum-mechanical localization of protonated and deterated isotopes in the symmetric low-barrier hydrogen-bonds of potassium dihydrogen phosphate (KDP) crystals in the paraelectric phase. The spatial density…
Molecular Dynamics is applied to Ferroelectric Perovskites in the framework of a first-principles derived effective Hamiltonian (Zhong, Vanderbilt, Rabe, Phys. Rev. Lett. {\bf 73} (1994), 1861). The degrees of freedom, that obey the Newton…
The three dimensional distribution of the X-ray diffuse scattering intensity of BaTiO$_3$ has been recorded in a synchrotron experiment and simultaneously computed using molecular dynamics simulations of a shell-model. Together these have…
Ferroelectric materials are the core of common technologies, such as medical ultrasound, mobile-phone antennae and low-power memory devices. The technological interest in ferroelectrics stems from the existence of switchable mesoscale…
We study theoretically the influence of the underlying domain microstructure on the electromechanical properties of ferroelectrics. Our calculations are based on a continuum approach that incorporates the long-range elastic and…
We present a first-principles study of model domain walls (DWs) in prototypic ferroelectric PbTiO3. At high temperature the DW structure is somewhat trivial, with atoms occupying high- symmetry positions. However, upon cooling the DW…