相关论文: Comparison of solid state crystallization of boron…

We report high pressure structural phase transformation sequence in a layered Iron-based superconducting compound FeSe0.3Te0.7 to 31 GPa at room temperature. The ambient pressure PbO type tetragonal phase (Space Group - P4/nmm) transforms…

Phase stability of various phases of MX (M = Ti, Zr; X = C, N) at equilibrium and under pressure is examined based on first-principles calculations of the electronic and phonon structures. The results reveal that all B1 (NaCl-type) MX…

The crystalline structures of lanthanum tetraboride, LaB4, under pressure are investigated using a genetic algorithm method coupled with first-principles calculations. We find two low-enthalpy phases for LaB4 as the thermodynamic ground…

Cubic boron phosphide BP has been studied in situ by X-ray diffraction and Raman scattering up to 55 GPa at 300 K in a diamond anvil cell. The bulk modulus of B0 = 174(2) GPa has been established, which is in excellent agreement with our ab…

Vacuum heat treatment of mechanically-alloyed powders of boron and aluminum leads to formation of a metastable Al-rich phase, which can be quenched. Its structure, composition, and thermal stability are established. With chemical formula…

The recent discovery of borophene, a two-dimensional allotrope of boron, raises many questions about its structure and its chemical and physical properties. Boron has a high chemical affinity to oxygen but little is known about the…

Molybdenum borides were studied theoretically using first-principles calculations, empirical total energy model and global optimization techniques to determine stable crystal structures. Our calculations reveal the structures of known Mo-B…

The complex crystal chemistry of elemental boron has led to numerous proposed structures with distinctive motifs as well as contradictory findings. Herein, evolutionary structure searches performed at 100 GPa have uncovered a series of…

An experimental and theoretical study of the structural properties of monoclinic bismuth oxide (alfa-Bi2O3) under high pressures is here reported. Both synthetic and mineral bismite powder samples have been compressed up to 45 GPa and their…

Different phases of solid boron under high pressure are studied by first principles calculations. The $\alpha$-B$_{12}$ structure is found to be stable up to 270 GPa. Its semiconductor band gap (1.72 eV) decreases continuously to zero…

Using first-principles molecular dynamics, we calculated the equation of state and shock Hugoniot of various boron phases. We find a large mismatch between Hugoniots based on existing knowledge of the equilibrium phase diagram and those…

Our first-principles computations show that the ground state of PbTiO$_3$ under hydrostatic pressure transforms discontinuously from $P4mm$ to $R3c$ at 9 GPa. Spontaneous polarization decreases with increasing pressure so that the $R3c$…

Disordering of solids typically leads to amorphization, but polymorph transitions, facilitated by favorable atomic rearrangements, may temporarily help to maintain long-range periodicity in the solid state. In far-from-equilibrium…

The high-pressure behaviour of PbS was investigated by angular dispersive X-ray powder diffraction up to pressures of 6.8 GPa. Experiments were accompanied by first principles calculations at the density functional theory level. By…

Two novel of boron-rich selenides, orthorhombic B$_6$Se and rhombohedral B$_{12}$Se, have been recently synthesized at high pressure - high temperature conditions. Room-temperature compressibilities of these phases were studied in a diamond…

SrAl2Si2 crystallizes into either a semimetallic, CaAl2Si2-type, \alpha phase or a superconducting, BaZn2P2-type, \beta phase. We explore possible \alpha --Pc;Tc--> \beta transformations by employing pressure- and temperature-dependent…

Over the last decade experimental studies have shown a large B isotope fractionation between materials carrying boron incorporated in trigonally and tetrahedrally coordinated sites, but the mechanisms responsible for producing the observed…

The formation of boron carbide under high pressures and from elemental reactants has been studied and optimum parameters have been determined by varying the (P, T, reactants) conditions. To this end, stoichiometric mixtures of commercial…

The effects of pressure on the crystal structure of the three known polymorphs of magnesium sulfate have been theoretically study by means of DFT calculations up to 45 GPa. We determined that at ambient conditions gamma MgSO4 is an unstable…

Studies of the behaviour of solids at ultra-high pressures, those beyond 200 GPa, contribute to our fundamental understanding of materials properties and allow an insight into the processes happening at such extreme conditions relevant for…