相关论文: Density functional theory study of the {\alpha} --…
Understanding the properties of molecular solids at high pressure is a key element in the development of new solid-state theories. However, the most commonly used generalized-gradient approximation (GGA) of the density functional theory…
In the present paper we generalised a phenomenological model developed in \cite{gomo:2005} for the description of magnetostructural phase transitions and related peculiarities of elastic properties in solid oxygen under high pressure and/or…
Structural phase transitions serve as the basis for many functional applications including shape memory alloys (SMAs), switches based on metal-insulator transitions (MITs), etc. In such materials, lattice incompatibility between phases…
Martensites are metastable phases, possessing a characteristic morphology, usually formed during a fast quench accross a structural transition. We attempt to understand these morphological features using a coarsegrained free energy…
Results of X-ray diffraction experiments on solid oxygen at low temperature and at pressures up to 10 GPa are presented.A careful sample preparation and annealing around 240 K allowed to obtain very good diffraction patterns in the…
We consider an off-lattice liquid crystal pair potential in strictly two dimensions. The potential is purely repulsive and short-ranged. Nevertheless, by means of a single parameter in the potential, the system is shown to undergo a…
An investigation of the pressure induced phase transition from the scheelite phase (I41/a, Z=4) to the fergusonite-like phase (I2/a, Z=4)/LaTaO(P21/c, Z=4) of LiYF4 is presented. Employing density functional theory (DFT) within the…
By the density functional theory for crystallization, it is shown that for vortex lines in an underlying layered structure a smectic phase with period m=2 can be stabilized by strong layer pinning. The freezing of vortex liquid is then…
The stability of MgH$_2$ has been studied up to 20~GPa using density-functional total-energy calculations. At ambient pressure $\alpha$-MgH${_2}$ takes a TiO$_2$-rutile-type structure. $\alpha$-MgH$_2$ is predicted to transform into…
We study the mechanics of temperature-driven reconstructive martensitic transformations in crystalline materials, within the framework of nonlinear elasticity theory. We focus on the prototypical case of the square-hexagonal transition in…
\textit{Ab initio} random structure searching based on density functional theory is used to determine the ground-state structures of ice at high pressures. Including estimates of lattice zero-point energies, ice is found to adopt three…
We systematically calculate the structure, formation enthalpy, formation free energy, elastic constants and electronic structure of Ti$_{0.98}$X$_{0.02}$ system by density functional theory (DFT) simulations to explore the effect of…
We report magnetization and differential thermal analysis measurements as a function of pressure accross the martensitic transition in magnetically superelastic Ni-Mn-In alloys. It is found that the properties of the martensitic…
The structure, lattice dynamics and mechanical properties of the magnesium hydroxide have been investigated with static density functional theory calculations as well as \it {ab initio} molecular dynamics. The hypothesis of a superstructure…
The cerium iso-structural phase transition (gamma to alpha) is dominated by f-electron localization changes that results in a magnetic ordering change and a volume collapse. Generally, these physics are difficult to capture with ab initio…
Classical density functional theory (DFT) is a statistical mechanical theory for calculating the density profiles of the molecules in a liquid. It is widely used, for example. to calculate the density distribution of the molecules in the…
Density-functional theory is utilized to investigate the zero-temperature transition from a Fermi liquid to an inhomogeneous stripe, or Wigner crystal phase, predicted to occur in a one-component, spin-polarized, two-dimensional dipolar…
The celebrated work of Onsager on hard particle systems, based on the truncated second order virial expansion, is valid at relatively low volume fractions for large aspect ratio particles. While it predicts the isotropic-nematic phase…
The high-pressure structural behavior of lanthanum monochalcogenides is investigated by theory and experiment. Theory comprises density functional calculations of LaS, LaSe and LaTe with the general gradient approximation for exchange and…
An effect of the volume change upon proper ferroelastic (martensitic) phase transitions in cubic crystals is considered. Corresponding terms in the Ginzburg-Landau expansion of the Gibbs free energy are analyzed for the first- as well as…