Related papers: Vortex-to-Polarization Phase Transformation Path i…
Using first-principles based effective Hamiltonian and finite temperature Monte Carlo simulations we investigate cooperative responses, as well as microscopic mechanism for vortex switching, in zero-dimensional Pb(Zr$_{0.5}$Ti$_{0.5}$)O$_3$…
The past decade's discovery of topological excitations in nanoscale ferroelectrics has turned the prevailing view that the polar ground state in these materials is uniform. However, the systematic understanding of the topological polar…
In the early 2000s, low dimensional systems were predicted to have topologically nontrivial polar structures, such as vortices or skyrmions, depending on mechanical or electrical boundary conditions. A few variants of these structures have…
Size-driven transition of an antiferroelectric into a polar ferroelectric or ferrielectric state is a strongly debated issue from both experimental and theoretical perspectives. While critical thickness limits for such transitions have been…
We describe ferroelectric thin films with circular electrodes and develop a thermodynamic theory that explains previously mysterious experiments. It is found to be especially useful for restricted geometries such as microstructures for…
Composite materials comprised of ferroelectric nanoparticles in a dielectric matrix are being actively investigated for a variety of functional properties attractive for a wide range of novel electronic and energy harvesting devices.…
Vortex crystals are commonly observed in ultra-thin ferroelectrics. However, a clear physical picture of origin of this topological state is currently lacking. Here, we show that vortex crystallization in ultra-thin Pb(Zr0.4,Ti0.6)O3 films…
The wealth of complex polar topologies recently found in nanoscale ferroelectrics result from a delicate balance between the materials intrinsic tendency to develop a homogeneous polarization and the electric and mechanic boundary…
Ferroelectrics are characterized by domain structures as are other ferroics. At the nanoscale though, ferroelectrics may exhibit non-trivial or exotic polarization configurations under proper electrostatic and elastic conditions. These…
We report from first-principles-based atomistic simulations that ferroelectricity can be sustained in PbTiO3 nanoparticles of only a few lattice constants in size as a result of a toroidal ordering. We found that size-induced topological…
In the micro- and nanoscale ferroelectric samples, the formation and the growth of domains are the usual stages of the polarization switching mechanism. By assuming the weak polarization anisotropy and by solving the…
Many dipolar topological structures have been experimentally demonstrated in (PbTiO$_3$)$_n$/(SrTiO$_3$)$_n$ superlattices, such as flux-closure, vortice, and skyrmion. In this work, we employ deep potential molecular dynamics (MD) to…
Ferroelectricity, a hallmark of spontaneous inversion-symmetry breaking, has been a central concept in condensed matter physics and functional materials research, yet recent discoveries are revealing that switchable polarization can emerge…
The structural and polar properties of BiFeO3 at finite temperature are investigated using an atomistic shell model fitted to first-principles calculations. Molecular Dynamics simulations show a direct transition from the low-temperature…
Bounded charges induced by the polarization gradient in finite-size ferroelectrics are known to produce the unfavorable depolarization electric field that suppresses the uniform ferroelectric state. To reduce the depolarization energy the…
The piezoelectric response is a measure of the sensitivity of a material's polarization to stress or its strain to an applied field. Using in-operando x-ray Bragg coherent diffraction imaging, we observe that topological vortices are the…
Ferroelectric switching in BiFeO$_3$ multiferroic thin films with intrinsic ``stripe-like'' and ``bubble-like'' polydomain configurations was studied by piezoresponse force microscopy. Using the local electric field applied by a scanning…
Using a first-principles-based approach, we determine the ferroelectric pattern in PbZr$_{0.5}$Ti$_{0.5}$O$_3$ ultrathin film. It is found that vortex stripes are formed in the system and they are responsible for the 180$^\circ$ domains…
Ferroelectric materials embedded with dielectric inclusions offer a unique platform for exploring novel topological polar textures. Using first-principles-based atomistic simulations, we investigate the polarization behavior of a BaTiO$_3$…
The size effect in ferroelectrics is treated as a competition between the geometrical symmetry of the ferroelectric sample and its crystalline symmetry. The manifestation of this competition is shown to be polarization rotation, which is…