Related papers: Atomistic Description for Temperature-Driven Phase…
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…
Barium titanate (BTO) is a representative perovskite oxide that undergoes three first-order ferroelectric phase transitions related to exceptional functional properties. In this work, we develop two atomic cluster expansion (ACE) models for…
The experimentally observed temperature dependence of the quartic coefficients in the Landau-Devonshire expansion for BaTiO_3 is naturally accounted for within a proper fluctuation model. It is explained, in particular, why one of the…
Despite important breakthroughs in the last decade, the calculation of temperature dependent properties of solids still remains a challenging task, especially in the vicinity of structural phase transitions. We show that the combination of…
The phase transition behaviour of PbTiO3 and BaTiO3 under (111) epitaxial strain is investigated using density-functional theory calculations. From tensile strains of +0.015 to compressive strains of -0.015, PbTiO3 undergoes phase…
We investigate the influence of quantum effects on the dielectric and piezoelectric properties of barium titanate in its (low-temperature) rhombohedral phase, and show the strongly anharmonic character of this system even at low…
We have developed first-principles models, based on a general parametrization of the full potential-energy surface, to investigate the lattice-dynamical properties of perovskite oxides. We discuss the application of our method to prototypic…
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…
Tracer diffusion experiments and metadynamics (MtD) simulations were used to study the diffusion of Ba cations in the cubic phase of the perovskite oxide BaTiO$_3$. $^{130}$BaTiO$_3$ thin films were used as diffusion sources to introduce…
Chalcogenide perovskites are lead-free materials for potential photovoltaic or thermoelectric applications. BaZrS$_3$ is the most studied member of this family due to its superior thermal and chemical stability, desirable optoelectronic…
The accurate description of the structural and thermodynamic properties of ferroelectrics has been one of the most remarkable achievements of Density Functional Theory (DFT). However, running large simulation cells with DFT is…
The stability, electronic structure, optical and thermoelectric properties of Te-doped BaTiO3 are investigated by first-principal calculation based on the density functional theory and Boltzmann transport theory implemented in WIEN2K and…
Information about the crystal structures in the range of morphotropic phase boundary of ferroelectric perovskite solid solutions is important for understanding their intricate properties which result in wide opportunities for practical…
The crystal structures and phonon spectra of orthorhombic cadmium titanate with the $Pbnm$ structure and of its two possible ferroelectrically distorted phases with $Pbn2_1$ and $Pb2_1m$ space groups were calculated from first principles…
Transition metal oxides are considered promising thermoelectric materials for harvesting high-temperature waste heat due to their stability, abundance and low toxicity. Despite their typically strong ionic character, they can exhibit…
The low thermal conductivity of piezoelectric perovskites is a challenge for high power transducer applications. We report first principles calculations of the thermal conductivity of ferroelectric PbTiO$_3$ and the cubic nearly…
In recent yerars, Bismuth sodium titanate (BNT) and BNT-based piezoelectric materials have proved potential for lead-free piezoelectric technologies. Such materials' complicated phase structure is crucial to their thermo-electromechanical…
Correct phenomenological description of ferroelectric phase transitions in barium titanate requires accounting for eighth-order terms in the free energy expansion, in addition to the conventional sixth-order contributions. Another unusual…
Motivated by the colossal negative thermal expansion recently found in BiNiO$_3$, the valence transition accompanied by the charge transfer between the Bi and Ni sites is theoretically studied. We introduce an effective model for Bi-$6s$…
When calcium titanate crystals are grown from stoichiometric melts, they crystallize in the cubic perovskite structure. Upon cooling to room temperature they undergo subsequent phase transitions to tetragonal and orthorhombic modifications.…