Related papers: Defect ordering and defect-domain wall interaction…
The (001) surfaces of polar perovskites BaTiO$_3$ and PbTiO$_3$ have been studied from first principles at T=0 K. For both cases of polarization, the most stable TiO-terminated interfaces show intrinsic ferroelectricity. In the topmost…
(Ba,Ca)TiO$_3$ and Ba(Ti,Zr)O$_3$ solid solutions are the building blocks of lead-free piezoelectric materials that attract a renewed interest. We investigate the properties of these systems by means of first-principles calculations, with a…
Artificial PbTiO$_{3}$/SrTiO$_{3}$ superlattices were constructed using off-axis RF magnetron sputtering. X-ray diffraction and piezoelectric atomic force microscopy were used to study the evolution of the ferroelectric polarization as the…
Ferroelectric domain walls are a rich source of emergent electronic properties and unusual polar order. Recent studies showed that the configuration of ferroelectric walls can go well beyond the conventional Ising-type structure. N\'eel-,…
The Landau theory of 180 degrees domain walls in BaTiO3 type ferroelectric particles is presented. Results of exact description of domain walls in bulk enabled us to formulate variational approach to theory of domain walls in corresponding…
Defect engineering using self-doping or creating vacancies in polycrystalline oxide based materials has profound influence on optical absorption, UV photo detection, and electrical switching. However, defects induced semiconducting oxide…
The defect chemistry of perovskite compounds is directly related to the stoichiometry and to the valence states of the transition-metal ions. Defect engineering has become increasingly popular as it offers the possibility to influence the…
Polar discontinuities occurring at interfaces between two different materials constitute both a challenge and an opportunity in the study and application of a variety of devices. In order to cure the large electric field occurring in such…
Perovskite oxides form an eclectic class of materials owing to their structural flexibility in accommodating cations of different sizes and valences. They host well known point and planar defects, but so far no line defect has been…
Domain walls are the topological defects that mediate polarization reversal in ferroelectrics, and they may exhibit quite different geometric and electronic structures compared to the bulk. Therefore, a detailed atomic-scale understanding…
Using density-functional calculations we study the structure and polarization response of tetragonal PbTiO3, BaTiO3 and SrTiO3 in a strain regime that is previously overlooked. Different from common expectations, we find that the…
We have investigated the atomistic structure of the 180-degree and 90-degree domain boundaries in the ferroelectric perovskite compound PbTiO3 using a first-principles ultrasoft-pseudopotential approach. For each case we have computed the…
The polar metal is a material that hosts both polar distortion and metallicity. Such a material is expected to show exotic magneto-electric phenomena if superconducts. Here, we theoretically explore ferroelectric and superconducting…
Double perovskite oxides (DPOs) with two transition metal ions ($A_2$$BB^\prime$O$_6$) offer a fascinating platform for exploring exotic physics and practical applications. Studying these DPOs as ultrathin epitaxial thin films on single…
SrTiO$_3$ is an incipient ferroelectric on the verge of a polar instability, which is avoided at low temperatures by quantum fluctuations. Within this unusual quantum paraelectric phase, superconductivity persists despite extremely dilute…
Using density functional theory (DFT), this work explores barium zirconate doped with nitrogen. In addition, we used density functional theory (DFT) to study the BaZrO$_3$'s electrical, optical, and structural properties, and we found that…
The functional properties of transition metal perovskite oxides are known to result from a complex interplay of magnetism, polarization, strain, and stoichiometry. Here, we show that for materials with a cooperative Jahn-Teller distortion,…
Ferroelectric charged domain walls are known for their high electrical conductivity, making them promising candidates for applications in modern electronics. A remarkably high conductivity and nominal charge density has been found in the…
The addition of electron donors to the vacant A site of defect-perovskite structure tungsten trioxide causes a series of structural and chemical phase transitions; for instance, in the well-known case of the sodium tungsten bronzes…
The stoichiometric antiferromagnetic insulator EuTiO$_3$ is proximate to a ferroelectric phase. Whereas cation substitution has been used as a tuning parameter to introduce charge carriers and manipulate the magnetism, the effects of…