Related papers: Novel hydrogen clathrate hydrate
Two solid phases of cyclohexane have been investigated over a temperature range spanning 13 to 266 K on a powdered, perdeuterated sample using neutron total scattering. Phase II has an ordered structure (C2/c) that forms below 186 K.…
We have developed x-ray diffraction measurements with high energy-resolution and accuracy to study water structure at three different temperatures (7, 25 and 66 C) under normal pressure. Using a spherically curved Ge crystal an energy…
Old and novel layered structures are attracting increasing attention for their physical, electronic, and frictional properties. SiS$_2$, isoelectronic to SiO$_2$, CO$_2$ and CS$_2$, is a material whose phases known experimentally up to 6…
Two novel three-dimensional (3D) crystal structures of carbon (C) and germanium carbide (GeC2) were predicted using first-principles density-functional theory (DFT) calculations. These newly discovered 3D carbon allotrope and GeC2 are in…
The discoveries of high-temperature superconductivity in H3S and LaH10 have excited the search for superconductivity in compressed hydrides. In contrast to rapidly expanding theoretical studies, high-pressure experiments on hydride…
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…
The discovery of a superconducting phase in sulfur hydride under high pressure with a critical temperature above 200 K has provided a new impetus to the search for even higher $T_c$. Theory predicted and experiment confirmed that the phase…
It has been suggested that high-density amorphous (HDA) ice is a structurally arrested form of high-density liquid (HDL) water, while low-density amorphous (LDA) ice is a structurally arrested form of low-density liquid (LDL) water. Recent…
Recent experimental developments in hydrogen-rich materials in high pressures have put this class of materials above others in the race toward room temperature superconductivity. As it is the basis of all the materials in this class, the…
Single crystals of a novel ruthenate, Ca2Ru2O7, were obtained. An X-ray diffraction study on a single crystal revealed that this material crystallizes in a pyrochlore structure with a lattice parameter, a = 10.197 Angstroms. The magnetic…
The study of superconductivity in compressed hydrides is of great interest due to measurements of high critical temperatures (Tc) in the vicinity of room temperature, beginning with the observations of LaH10 at 170-190 GPa. However, the…
We have performed ultrasonic measurements on single-crystalline URu2Si2 with pulsed magnetic fields, in order to check for possible lattice instabilities due to the hybridized state and the hidden-order state of this compound. The elastic…
As an A-site-vacant perovskite-type oxide, ReO3 undergoes sequential pressure-driven structural transitions associated with the rotation of ReO6 octahedra. The rhombohedral-I phase in the pressure range of 12-39 GPa is featured by a lattice…
Since the discovery of superconductivity at 200 K in H3S [1] similar or higher transition temperatures, Tcs, have been reported for various hydrogen-rich compounds under ultra-high pressures [2]. Superconductivity was experimentally proved…
Using variable temperature scanning tunneling microscopy and dI/dz barrier height spectroscopy, the structure of water on h-BN/Rh(111) nanomesh has been investigated. Below its desorption temperature, two distinct phases of water…
Changes in atomic coordination numbers at high pressures are fundamental to condensed-matter physics because they initiate the emergence of unexpected structures and phenomena. Silicon is capable of forming eight-, nine-, and…
The phase diagram of oxygen is investigated for pressures from 50 to 130~GPa and temperatures up 1200 K using first principles theory. A metallic molecular structure with the $P6_3/mmc$ symmetry ($\eta^{'}$ phase) is determined to be…
Disorder-induced ordering and unprecedentedly high radiation tolerance in $\gamma$-phase of gallium oxide is a recent spectacular discovery at the intersection of the fundamental physics and electronic applications. Importantly, by far,…
Computational searches for stable and metastable structures of water ice and other H:O compositions at TPa pressures have led us to predict that H$_2$O decomposes into H$_2$O$_2$ and a hydrogen-rich phase at pressures of a little over 5…
The pressure-induced transformation of diatomic nitrogen into non-molecular polymeric phases may produce potentially useful high-energy-density materials. We combine first-principles calculations with structure searching to predict a new…