Related papers: Coupling between small polarons and ferroelectrici…
The present {\em ab initio} study shows that in BaBiO$_3$, Bi$^{3+}$ sites can trap two holes from the valence band to form Bi$^{5+}$ cations. The trapping is accompanied by large local lattice distortions, therefore the composite particle…
Controlling the effects of photoexcited polarons in transition metal oxides can enable the long timescale charge separation necessary for renewable energy applications as well as controlling new quantum phases through dynamically tunable…
The electronic structures of ABO3 ferroelectrics are calculated within the density functional theory, and their evolution is analyzed as the crystal-field symmetry changes from cubic to rhombohedral via tetragonal phases. Electronic…
Electric conductivity and structural details of the hole-doped polaron conductor La0.9Sr0.1FeO3 (LSF10) are reported. The conductivity of a single crystal shows an exponential increase with temperature with a maxi-mum of 100 S/cm at 700 K…
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…
Ferroelectric domain walls are planes within an insulating material that can accumulate and conduct charge carriers, hence the interaction of the domain walls with the charge carriers can be important for photovoltaic and other electronic…
The phonon spectrum of cubic cadmium metastannate and the crystal structures of its distorted phases were calculated from first principles within the density functional theory. It is shown that the phonon spectrum and the energy spectrum of…
Solid solution BiFe1-xCoxO3 shows anti-ferromagnetic order and pyroelectric order, simultaneously. It has been known that BiFe1-xCoxO3 exhibits a structural phase transition between monoclinic and tetragonal phases as x increases. This…
By using a symmetry motivated basis to evaluate local distortions against pair distribution function data (PDF), we show without prior bias, that the off-centre Ti displacements in the archetypal ferroelectric BaTiO3 are zone centred and…
In ferroelectricity, atomic-scale dipole moments interact collectively to produce strong electro-mechanical coupling and switchable macroscopic polarization. Hence, the functionality of ferroelectrics emerges at a solid-solid phase…
We describe length and time rescaling across the paraelectric to ferroelectric phase transition in BaTiO$_3$. Small ferroelectric clusters are unable to grow in the paraelectric phase and exist for a short period of time only. The onset of…
First principles calculations based on the density functional theory within the local spin density approximation plus U(LSDA+U)scheme, show rhombohedral Bi$_2$FeTiO$_6$ is a potential multiferroic in which the magnetism and ferroelectricity…
We present a spatial and wave-vector resolved study of the electronic structure of micron sized ferroelectric domains at the surface of a BaTiO3(001) single crystal. The n-type doping of the BaTiO3 is controlled by in-situ vacuum and oxygen…
This review will deal with several types of free charge localisation in oxides and their consequences on the effective dielectric spectra of such materials. The first one is the polaronic localisation at the unit cell scale on residual…
Ferroelectric polar displacements have recently been observed in conducting electron-doped BaTiO3. The co-existence of a ferroelectric phase and conductivity opens the door to new functionalities which may provide a unique route for novel…
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…
Motivated by the puzzling report of the observation of a ferromagnetic insulating state in LaMnO$_3$/SrTiO$_3$ heterostructures, we calculate the electronic and magnetic state of LaMnO$_3$, coherently matched to a SrTiO$_3$ square substrate…
As a prototypical Mott insulator with ferromagnetic ordering, YTiO3 (YTO) is of great interest in the study of strong electron correlation effects and orbital ordering. Here we report the first molecular beam epitaxy (MBE) growth of YTO…
Structural softness - often characterized by unstable phonon modes and large electromechanical responses - is a hallmark of ferroelectric perovskites like BaTiO3 or Pb(Ti,Zr)O3. Whether HfO2 ferroelectrics present any such structural…
We have proposed the polarization rotation theory to understand the underlying physics of the large piezoelectric effect in ferroelectric crystals by referring to the coherent rotation model in ferromagnetism. When both the electric field…