Related papers: Metallic Hydrogen: Experiments on Metastability
Dielectric response in methanol measured in wide pressure and temperature range ($P < 6.0$ GPa; 100 K $<T<$ 360 K) reveals a series of anomalies which can be interpreted as a transformation between several solid phases of methanol including…
Isolated hydrogen, deuterium, and muonium in diamond have been studied by path-integral molecular dynamics simulations in the canonical ensemble. Finite-temperature properties of these point defects were analyzed in the range from 100 to…
The electrical conductivity and Raman spectroscopy measurements have been performed on MoS$_2$ at high pressures up to 90 GPa and variable temperatures down to 5 K. We find that the temperature dependence of the resistance in a metallic…
We refer to our recent calculations (Eur. Phys. J. B, \textbf{86}, 252 (2013)) of metallization pressure of the three-dimensional simple-cubic crystal of atomic hydrogen and study the effect on the crucial results concocting from…
Lattice stability and metastability, as well as melting, are important features of the physics and chemistry of dense hydrogen. Using ab initio molecular dynamics (AIMD), the classical superheating limit and melting line of metallic…
Methanol is a potentially important impurity in subsurface oceans on Titan and Enceladus. We report measurements of the freezing of methanol-water samples at pressures up to 350~MPa using a volumetric cell with sapphire windows. For low…
Knowledge of the behavior of hydrogen in metal hydrides is the key for understanding their electronic properties. So far, no experimental methods exist to access these properties beyond 100 GPa, where high-Tc superconductivity emerges.…
Recently, several research groups announced reaching the point of metallization of hydrogen above 400 GPa. Following the mainstream of extensive investigations of compressed polyhydrides, in this work we demonstrate that small (4 atom %)…
Metallic hydrogen, existing in remarkably extreme environments, was predicted to exhibit long-sought room-temperature superconductivity. Although the superconductivity of metallic hydrogen has not been confirmed experimentally,…
We performed ac-susceptibility measurements of magnesium diboride powder samples under pure hydrostatic pressures up to 0.4 GPa and under quasi-hydrostatic pressure conditions up to 8 GPa in a helium gas pressure cell and a diamond-anvil…
Hydrogen-rich compounds have been extensively studied both theoretically and experimentally in the quest for novel high-temperature superconductors. Reports on sulfur-hydride attaining metallicity under pressure and exhibiting…
We present first-principles calculations of metallic atomic hydrogen in the 400-600 GPa pressure range in a tetragonal structure with space group $I4_1/amd$, which is predicted to be its first atomic phase. Our calculations show a band…
The dependence of Tc on nearly hydrostatic pressure has been measured for an isotopically pure (11B) MgB2 sample in a helium-loaded diamond-anvil-cell to nearly 20 GPa. Tc decreases monotonically with pressure from 39.1 K at ambient…
We have performed quantum molecular-dynamics simulations for methane under shock compressions up to 80 GPa. We obtain good agreement with available experimental data for the principal Hugoniot, derived from the equation of state. A…
A reliable process for compressing hydrogen and for removing all contaminants is that of the metal hydride thermal compression. The use of metal hydride technology in hydrogen compression applications though, requires thorough structural…
We have produced and observed metastable solid helium-4 below its melting pressure between 1.1 K and 1.4 K. This is achieved by an intense pressure wave carefully focused inside a crystal of known orientation. An accurate density map of the…
We have performed a combined experimental and theoretical study of ethane and methane at high pressures up to 120 GPa at 300 K using x-ray diffraction and Raman spectroscopy and the USPEX ab-initio evolutionary structural search algorithm,…
A recent paper by Zaghoo et al. presents optical data at high-pressure and high-temperature and interprets the data as evidence for a first-order phase transition to metallic hydrogen during heating. Here we argue that the presented data…
Metallic hydrogen is capable of showing room temperature superconductivity, but its experimental syntheses are extremely hard. Therefore, it is desirable to reduce the synthesis pressure of metallic hydrogen by adding other chemical…
Hydrogen sulfide (H2S) is a prototype molecular system and a sister molecule of water. The phase diagram of solid H2S at high pressures remains largely unexplored arising from the challenges in dealing with the looser S-H bond and larger…