相关论文: Phase Transition Mechanism of Hexagonal Graphite t…
The lighter group-V element phosphorus forms the As-type (hR2) structure under pressure, above 5 GPa, and at 10 GPa transforms to the simple cubic structure (cP1), similar to arsenic. Despite of its low packing density, the simple cubic…
Ab initio molecular dynamic method within the framework of density functional theory is applied to analyze the structural and electronic properties of crystalline molecular hydrogen at temperature 100\,K. Pressure, pair correlation function…
In their recent work Dias and Silvera (Science 2017) claim to have observed the Wigner-Huntington transition of hydrogen to a metallic state (MH) at a pressure of 495 GPa at low temperatures. The evidence for this transition is based on a…
In this lecture we review high-pressure phase transition sequences exhibited by simple elements, looking at the examples of the main group I, II, IV, V, and VI elements. General trends are established by analyzing the changes in…
We analyze the pressure-induced metal-insulator transition in a two-dimensional vertical stack of $H_2$ molecules in x-y plane, and show that it represents a striking example of the Mott-Hubbard-type transition. Our combined exact…
We investigate the high temperature phase of a dilaton flow deformation of the AdS/CFT Correspondence. We argue that these geometries should be interpreted as the N=4 gauge theory perturbed by a SO(6) invariant scalar mass and that the…
We provide a description of phase transitions at finite temperature in strongly coupled field theories using holography. For this purpose, we introduce a general class of gravity duals to superconducting theories that exhibit various types…
Through a systematic structural search we found an allotrope of carbon with Cmmm symmetry which we predict to be more stable than graphite for pressures above 10 GPa. This material, which we refer to as Z-carbon, is formed by pure sp3 bonds…
The high-temperature cubic-tetragonal phase transition of pure stoichiometric zirconia is studied by molecular dynamics (MD) simulations and within the framework of the Landau theory of phase transformations. The interatomic forces are…
By employing first-principles metadynamics simulations, we explore the 300 K structures of solid hydrogen over the pressure range 150-300 GPa. At 200 GPa, we find the ambient-pressure disordered hexagonal close-packed (hcp) phase transited…
We present results from ramp compression experiments on high-purity Zr that show the $\alpha \rightarrow \omega$, $\omega \rightarrow \beta$, as well as reverse $\beta \rightarrow \omega$ phase transitions. Simulations with a multi-phase…
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…
We present the results of molecular dynamics (MD) studies of hexane physisorbed onto graphite for eight coverages in the range $0.875 \le \rho \le 1.05$ (in units of monolayers). At low temperatures the adsorbate molecules form a uniaxially…
We theoretically study high-harmonic generation (HHG) from solids driven by intense laser pulses using a one-dimensional model periodic crystal. By numerically solving the time-dependent Schr\"{o}dinger equation directly on a real-space…
A cascade of phase transitions from square to hexagonal lattice is studied in 2D system of particles interacting via core-softened potential. Due to the presence of two length-scales of repulsion, different local configurations with four,…
Some highly unusual features of a lipid-water liquid crystal are revealed by high pressure x-ray diffraction, light scattering and dilatometric studies of the lamellar (bilayer $L_{\alpha}$) to nonlamellar inverse hexagonal ($H_{II}$) phase…
We study the zero-temperature phase diagram of two-dimensional helium-4 using neural quantum states. Our variational description allows us to address liquid and solid phases using the same functional form as well as exploring possible…
Atoms at liquid metal surfaces are known to form layers parallel to the surface. We analyze the two-dimensional arrangement of atoms within such layers at the surface of liquid sodium, using ab initio molecular dynamics (MD) simulations…
The high-pressure behavior of monoclinic VO$_2$ is revisited by a combination of Raman spectroscopy and X-ray diffraction on a single crystal under hydrostatic conditions at room temperature. A soft mode is observed up to P$_c$ = 13.9(1)…
Silicon exhibits several metastable allotropes which recently attracted attention in the quest for materials with superior (e.g. optical) properties, compatible with Si technology. In this work we shed light on the atomic-scale mechanisms…