Related papers: Conservation of dielectric constant upon amorphiza…
Polar metals are rare because free carriers in metals screen electrostatic potential and eliminate internal dipoles. Degenerate doped ferroelectrics may create an approximate polar metallic phase. We use first-principles calculations to…
For decades it has been a well-known fact that among the few ferroelectric compounds in the perovskite family namely BaTiO3, KNbO3, PbTiO3 Na1/2Bi1/2TiO3 the dielectric and piezoelectric properties of BaTiO3 is considerably higher than the…
The dielectric response of surface stabilized ferroelectric liquid crystals with chevron layer structure is studied within low and intermediate frequency ranges, characteristic for collective molecular excitations. By analytically solving…
AgNbO$_3$ is a lead-free perovskite with considerable potential for energy storage and optoelectronic applications, yet its low-temperature crystal structure has remained controversial. In this Letter, we revisit its low-energy structural…
We introduce columnar shifts---collective rigid-body translations---as a structural degree of freedom relevant to the phase behaviour of molecular perovskites ABX$_{\textrm3}$ (X = molecular anion). Like the well-known octahedral tilts of…
A single crystal of lead-zirconate-titanate (PZT), composition Pb(Zr0.80Ti0.20)O3, was studied by polarized-Raman scattering as a function of temperature. Raman spectra reveal that the local structure deviates from the average structure in…
We studied structural, electronic and magnetic properties of a cubic perovskite BaFeO$_{3-\delta}$ ($0 \le \delta \le 0.5$) within the density functional theory using a generalized gradient approximation and a GGA+U method. According to our…
The anharmonic lattice dynamics of oxide and halide perovskites play a crucial role in their mechanical and optical properties. Raman spectroscopy is one of the key methods used to study these structural dynamics. However, despite decades…
Li containing transition metal oxides are known as good ionic conductors. Performing classical molecular dynamics simulations, the diffusion behavior of Li ions is investigated in crystalline and amorphous phases with the stoichiometries…
We have performed detailed first-principles calculations to determine the eigenvectors of the zone-center modes of hexagonal BaTiO3 and shown that the experimentally relevant low-energy modes (including the non-polar instability) can be…
Low-dimensional ferroelectricity and polar materials have attracted considerable attentions for their fascinating physics and potential applications. Based on first-principles calculations, here we investigate the stacking modes and polar…
Density functional theory calculations have been performed for the structural, electronic, magnetic and ferroelectric properties of a mixed-valence Fe(II)-Fe(III) formate framework [NH$_2$(CH$_3$)$_2$][Fe$^{\rm III}$Fe$^{\rm II}$(HCOO)$_6$]…
The functionality of ferroelectrics is often constrained by their Curie temperature, above which depolarization occurs. Lithium (Li) is the only experimentally known substitute that can increase the Curie temperature in ferroelectric…
Some of (1-x)NaNbO_3-(x)ABO_3 perovskite solid solutions exhibit a dramatic diffusion of the dielectric permittivity epsilon' maximum and relaxor-type behavior when the second component concentration exceeds a threshold value x_0. The…
The macroscopic dielectric permittivity of dielectric crystals is related to the microscopic atomic polarizability of constituent atoms by the known Clausius-Mossotti relation obtained in the middle of 19th century. We derive a similar…
A correlation between structure and vibrational properties related to a ferroelectric to paraelectric phase transition in perovskite Pb(1-x)(Na0.5Sm0.5)xTiO3 (PNST - x) polycrystalline powders is discussed. Substitution leads to reduction…
The cubic perovskite-related ceramic CaCu3Ti4O12 has a very high static dielectric constant ~10000 at room temperature (RT), which drops to about 100 below about 100 K. Substituting Cd for Ca reduces the RT value of the dielectric constant…
Magnetically-driven ferroelectric atomic displacements of the order of 10$^{-3} Angstrom have been observed in orthorhombic (perovskite like) YMnO$_3$ by a single-crystal synchrotron x-ray diffraction. The refined polar structure shows the…
Density functional plus dynamical mean field calculations are used to show that in transition metal oxides, rotational and tilting (GdFeO$_3$-type) distortions of the ideal cubic perovskite structure produce a multiplicity of low-energy…
Relaxor ferroelectric perovskites are highly polarizable and can exhibit giant coupling between elastic strain and an applied electric field. Here, we report an in situ extended X-ray absorption fine structure (EXAFS) study of a…