相关论文: Diffusive phase transitions in ferroelectrics and …

This paper analyzes how the ferroelectric properties of cubic-like BiFeO$_3$ nanoparticles are affected by different terminations and charge distributions at the surface using ab-initio-based atomistic computational experiments. Our…

Proximity ferroelectricity is a novel paradigm for inducing ferroelectricity in a non-ferroelectric polar material such as AlN or ZnO that are typically unswitchable with an external field below their dielectric breakdown field. When placed…

We have used first-principles methods to investigate the phase diagram of multiferroic bismuth ferrite (BiFeO3 or BFO), revealing the energetic and vibrational features that control the occurrence of various relevant structures. More…

Molecular-dynamics simulations of KNbO$_3$ reveal preformed dynamic chain-like structures, present even in the paraelectric phase, that are related to the softening of phonon branches over large regions of the Brillouin zone. The phase…

We propose that the finite-frequency susceptibility of matter near a class of zero-temperature phase transition exhibits distinctive excitonic structure similar to meson resonances. The specific case of a Landau level undergoing a…

Phase-field simulation (PFS) have revolutionized the understanding of domain structure and switching behavior in ferroelectric thin films and ceramics. Generally, PFS is based on solution of a (set) of Ginzburg-Landau equations for a…

Ferroelectrics show a phase transition to a paraelectric phase at a well-defined transition temperature. Introducing disorder makes this transition diffuse, and the system becomes a relaxor. Since the degree of (dis-)order is usually…

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…

Low temperature studies of the behavior of the sound velocity and attenuation of acoustic modes have been performed on a single crystal NdFe_3(BO_3)_4. Transitions of the magnetic subsystem to the antiferromagnetically ordered state at T_N…

Ferroelectrics form domain patterns that minimize their energy subject to imposed boundary conditions. In a linear, constrained theory, that neglects domain wall energy, periodic domain patterns in the form of multi-rank laminates can be…

We have investigated the dielectric properties of Gd$_{1-x}$Tb$_{x}$MnO$_{3}$ crystals in magnetic fields to clarify the crossover between two distinct ferroelectric phases, GdMnO$_{3}$-type (first-order displacive) and TbMnO$_{3}$-type…

We present a quantitative analysis of the phonon lineshapes obtained by neutron inelastic scattering methods in the relaxor ferroelectric Pb(Mg1/3Nb2/3)O3 (PMN). Differences in the shapes and apparent positions of the transverse acoustic…

We propose mechanism for pressure-induced transitions between ferromagnetic and antiferromagnetic phases that relies on a competition between characteristic energy scales ubiquitous among $d$-electron metallic magnetic compounds. Principles…

We re-examine the nature of the ground states of bilayer graphene at odd integer filling factors within a simplified model of nearly degenerate $n=0$ and $n=1$ Landau levels. Previous Hartree-Fock studies have found that ferroelectric…

Recent discovery of the ferroelectric nematic phase N_F resurrects a question about stability of the uniform N_F state with respect to the formation of either standard for solid ferroelectrics domain structure, or often occurring in liquid…

We present a minimal Landau theory of plastic-to-crystal phase transitions in which the key components are a multipole-moment order parameter that describes the orientational ordering of the constituent molecules, coupling between such…

We demonstrate how the quantum paraelectric ground state of SrTiO$_3$ can be accessed via a microscopic $ab~initio$ approach based on density functional theory. At low temperature the quantum fluctuations are strong enough to stabilize the…

In this work, we investigate the accumulative polarization (P) switching characteristics of ferroelectric (FE) thin films under the influence of sequential electric-field pulses. By developing a dynamic phase-field simulation framework…

Dielectric tensor and lattice dynamics of alpha-PbO2-type TiO2 have been investigated using the density functional perturbation theory, with a focus on responses of the vibrational frequencies to pressure. The calculated Raman spectra under…

The magnetic phases of hexagonal perovskites RMnO_3 (R=Ho, Er, Tm, Yb, Sc, Y) are analysed using group theory and the Landau theory of phase transitions. The competition between various magnetic order parameters is discussed in the context…