Related papers: Absence of Metallization in Solid Molecular Hydrog…
Hydrogen is widely regarded as a cornerstone of future low-carbon energy technologies, yet the lack of safe, efficient, and reversible solid-state storage materials remains a major barrier to its large-scale deployment. Although porous…
We present extensive molecular dynamics (MD) simulations investigating numerous candidate crystal structures for hydrogen in conditions around the present experimental frontier (400GPa). Spontaneous phase transitions in the simulations…
Metallization and dissociation are key transformations in diatomic molecules at high densities particularly significant for modeling giant planets. Using X-ray absorption spectroscopy and atomistic modeling, we demonstrate that in halogens,…
A simple model of the molecular crystal of $N$ atoms as a statistical mixture in real space of $NX$ atoms in excited and $N(1-X)$ atoms in well localized ground state is considered. The phase coherence of the atomic wave functions is…
Aluminum hydride (alane) AlH_3 is an important material in hydrogen storage applications. It is known that AlH_3 exists in multiply forms of polymorphs, where $\alpha$-AlH_3 is found to be the most stable with a hexagonal structure. Recent…
In a recently published article [1], Ranga P. Dias & Isaac F. Silvera have reported the visual evidence of metallic hydrogen concomitantly with its characterization at a pressure of 495 GPa and low temperatures. We have expressed serious…
The metallic regime of the hydrogen plasma is studied by ab initio Molecular Dynamics simulations, for classical protons and fully degenerate electrons, in the strong coupling regime of the protons. The breakdown of linear screening…
The microscopic mechanism of the hydrogen-induced metal-insulator transition in SmNiO$_3$ is clarified by means of density-functional theory with the Hubbard U correction. While 100% of hydrogen doping per Ni atom has been supposed to be…
Hydrogen at high temperature and pressure undergoes a phase transition from a liquid molecular phase to a conductive atomic state, or liquid metallic hydrogen, sometimes referred to as the plasma phase transition (PPT). The PPT phase line…
The high-pressure phases of solid hydrogen are of fundamental interest and relevant to the interior of giant planets; however, knowledge of these phases is far from complete. Particle swarm optimization (PSO) techniques were applied to a…
Solid hydrogen sulfide is well known as a typical molecular crystal but its stability under pressure is still under debate. Particularly, Eremets et al. found the high pressure superconductivity with $T_{c}\approx$ 190 K in a H$_{2}$S…
We provide semi-rigorous arguments that the Homogeneous Electron Fluid (HEF) has a colloidal phase separating the Wigner Crystal from the high density fluid phase. Near the crossover between crystal and fluid ground state energies, the…
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…
Boron bulk crystals are marked by exceptional structural complexity and unusual related physical phenomena. Recent reports of hydrogenated $\alpha$-tetragonal and a new $\delta$-orthorhombic boron B$_{52}$ phase have raised many fundamental…
The possibility of metallic hydrogen was first mooted by Wigner and Huntington in 1935. Here it is show that the calculations from that paper are in remarkably good agreement with modern density functional theory results. The possibility…
Structural behavior and equation of state of atomic and molecular crystal phases of dense hydrogen at pressures up to 3.5 TPa are systematically investigated with density functional theory. The results indicate that the Vinet EOS model that…
Dias and Silvera (Letters, p. 715, 2017) claim the observation of the Wigner-Huntington transition to metallic hydrogen at 495 GPa. We show that neither the claims of the record pressure or the phase transition to a metallic state are…
We present a microscopic picture rationalizing the surprisingly steep decrease of the band gap with temperature in insulators, crystalline or otherwise. The gap narrowing largely results from fluctuations of long-wavelength optical…
We determine numerically the ground state of the two-dimensional, fully polarized electron gas within the Hartree-Fock approximation without imposing any particular symmetries on the solutions. At low electronic densities, the Wigner…
While most of the rare earth metals readily form trihydrides, due to increased stability of the filled 4f electronic shell for Yb(II), only YbH$_{2.67}$, formally corresponding to Yb$^{\rm II}$(Yb$^{\rm III}$H$_4$)$_2$ or Yb$_3$H$_8$,…