Related papers: Phase transitions in BaTiO$_3$ from first principl…
Ferroelectrics remain in the focus of scientific attention for decades owing to their fundamental and practical appeal. Recently, ferroelectricity has been demonstrated in semiconducting halide perovskites, offering both a rare combination…
We have studied ab initio the phase transition in PbZrO3, a perovskite oxide usually presented as the prototypic anti-ferroelectric material. Our work reveals the crucial role that anti-ferrodistortive modes -- involving concerted rotations…
We have used Monte Carlo simulation techniques to obtain the magnetic phase diagram of the double exchange Hamiltonian. We have found that the Berry's phase of the hopping amplitude has a negligible effect in the value of the magnetic…
We merge advanced ab initio schemes (standard density functional theory, hybrid functionals and the GW approximation) with model Hamiltonian approaches (tight-binding and Heisenberg Hamiltonian) to study the evolution of the electronic,…
We present an effective Hamiltonian based real-space approach for studying the weak-coupling Bardeen-Cooper-Schrieffer (BCS) to the strong-coupling Bose-Einstein condensate (BEC) crossover in the two-dimensional attractive Hubbard model at…
The structural phase transition in hexagonal BaMnO$_3$ occurring at $T_c$=130 K was studied in ceramic samples using electron and X-ray diffraction, second harmonic generation as well as by dielectric and lattice dynamic spectroscopies. The…
The ferroelectric to paraelectric phase transition in LiTaO$_3$ and in pure as well as Mg doped LiNbO$_3$ is investigated theoretically by atomistic calculations in the framework of the density functional theory, as well as experimentally…
First-principles total-energy calculations are carried out for (001) surfaces of the cubic perovskite ATiO3 compounds PbTiO3, BaTiO3, and SrTiO3. Both AO-terminated and TiO2-terminated surfaces are considered, and fully-relaxed atomic…
We study the energy gap between the ground state and the first excited state of a mean-field-type non-stoquastic Hamiltonian by a semi-classical analysis. The fully connected mean-field model with $p$-body ferromagnetic interactions under a…
First-principles calculations were performed to investigate the ferroelectric properties of barium titanate and bismuth ferrite, as well as phonon dispersion of BaTiO3, using density functional theory and density functional perturbation…
The current controversies about the existence of an intermediate 'beta' phase of BiFeO_3 and the high temperature paraelectric 'gamma' phase are resolved by studying the sequence of ferroic transitions in 0.8BiFeO_3-0.2Pb(Fe_1/2Nb_1/2)O_3…
We propose a relationship between thermodynamic phase transitions and ground-state quantum phase transitions in systems with variable Hamiltonian parameters. It is based on a link between zeros of the canonical partition function at complex…
A complete mapping in the Brillouin zone of the structural instability associated with the ferroelectric phase transitions of KNbO$_3$ has been obtained by first-principles calculations using an LAPW linear response approach. The wavevector…
We report the time dependent response of electrical resistivity in the non-magnetic perovskite oxide NdNiO$_3$ in its phase separated state and provide a physical explanation of the observations. We also model the system and do an accurate…
Relaxor ferrolectrics are important in technological applications due to a strong electromechanical response, energy storage capacity, electrocaloric effect, and pyroelectric energy conversion properties. Current efforts to discover and…
Specific heat studies of the Sr$_{1-x}$Ba$_x$Mn$_{1-y}$Ti$_y$O$_3$ polycrystalline samples performed by the relaxation and DSC methods over the temperature range 2 - 450 K are reported. Anomalies accompanying the…
First-order phase transitions produce gravitational waves and primordial black holes. They always occur in field theories where symmetries are radiatively broken and masses are correspondingly generated. These theories predict a period of…
Despite extensive research interests in perovskite oxides, low energy consumption, non-destructive and maneuverable methods for phase transition in perovskite oxides are still the under its exploration, and the underlying mechanisms remain…
The investigation of the structural phase transition in the vicinity of the Curie temperature $T_c$ of LiNb$_{1-x}$Ta$_x$O$_3$ crystals is motivated by the expected combination of advantageous high-temperature properties of LiNbO$_3$ and…
The technological performances of metallic compounds are largely influenced by atomic ordering. Although there is a general consensus that successful theories of metallic systems should account for the quantum nature of the electronic glue,…