Related papers: Determination of ferroelectric compositional phase…
(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…
We describe a general method to model multicomponent ordered crystals using the phase-field crystal (PFC) formalism. As a test case, a generic B2 compound is investigated. We are able to produce a line of either first-order or second-order…
Ba2CaMoO6 was synthesized by solid state method. The crystal structure adopts cubic Fm-3m space group at room temperature with lattice parameters of 8.378231(5) {angstroms}. Upon cooling, Ba2CaMoO6 was determined to have a structural phase…
Tetramethylammonium (TMA) cadmium azide, is a new perovskite-like compound which undergoes a series of first-order phase transitions, including a ferroelastic transition above room temperature. Understanding the order-disorder structural…
A comparative theoretical study is presented for the rhombohedral R3 and R3m phase HfO2, of two possible forms in its heavily Zr-doped ferroelectric thin films found recently in experiments. Their structural stability and polarization under…
We propose a pair-condensate variational approach (PCV) to determine a set of the most important collective pairs in the description of low-lying states in atomic nuclei. Having available the precise details on these key collective pairs --…
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…
SrTiO$_{3}$, a quantum paraelectric, becomes a metal with a superconducting instability after removal of an extremely small number of oxygen atoms. It turns into a ferroelectric upon substitution of a tiny fraction of strontium atoms with…
We report dielectric, thermodynamical, acoustic, and optical properties of a chiral molecular crystal, 1,1'-bi-2-naphthol 2-dimethylsulfoxide (BINOL2DMSO). We find two successive phase transitions at Tc1=190 K and Tc2=125 K. The first…
Cluster variation method (CVM) and path probability method (PPM) have generally been employed to study replacive phase transitions in alloy systems. Recently, displacive phase transitions have been explored within the realm of replacive…
Quasi-forbidden electronic transitions in atoms and quasi-degenerate vibronic transitions in molecules serve as powerful probes of hypothetical temporal variations of fundamental constants. Computation of the sensitivity of a transition to…
<001> oriented 0.7Pb(Mg1/3Nb2/3)O3-0.3PbTiO3 single crystals were poled under different electric fields, i.e. Epoling=4 kV/cm and Epoling=13 kV/cm. In addition to the temperature-dependent dielectric constant measurement, X-ray diffraction…
A realistic theory of the quantum paraelectric - ferroelectric transition is presented, involving parameters determined from band calculations and a renormalization group treatment of critical fluctuations. The effects of reduced…
The structure and the dielectric properties of Pb(Zn1/3Nb2/3)O3 (PZN) crystal have been investigated by means of high-resolution synchrotron x-ray diffraction (with an x-ray energy of 32 keV) and dielectric spectroscopy (in the frequency…
We present thermodynamic, structural and transport measurements on Ba(Fe0.973Cr0.027)2As2 single crystals. All measurements reveal sharp anomalies at ~ 112 K. Single crystal x-ray diffraction identifies the structural transition as a first…
A combined experimental and theoretical study is presented of the band gap of AlInN, confirming the breakdown of the virtual crystal approximation (VCA) for the conduction and valence band edges. Composition dependent bowing parameters for…
A new phase field crystal (PFC) type theory is presented, which accounts for the full spectrum of solid-liquid-vapor phase transitions within the framework of a single density order parameter. Its equilibrium properties show the most…
We observe a structural phase transition between two configurations of a superradiant crystal by coupling a Bose-Einstein condensate to an optical cavity and applying imbalanced transverse pump fields. We find that this first order phase…
LiCu_2O_2 single crystals were studied in the temperature range 300-1100 K by means of heating-cooling curves of differential thermal analysis (DTA), thermogravimetry (TG), X-ray powder diffraction and electrical measurements. A reversible…
Recently, a new orthorhombic phase has been discovered in the ferroelectric system Pb(Zn1/3Nb2/3)O3-xPbTiO3 (PZN-xPT) for x= 9%, and for x= 8% after the application of an electric field. In the present work, synchrotron x-ray measurements…