相关论文: Novel high-pressure calcium carbonates
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…
Carbon can exist as isolated dumbbell, one-dimensional (1D) chain, 2D plane, and 3D network in carbon solids or carbon-based compounds, which attributes to its rich chemical binding way, including sp-, sp2-, and sp3-hybridized bonds. Sp2…
Gas hydrates are systems of prime importance. In particular, hydrogen hydrates are potential materials of icy satellites and comets, and may be used for hydrogen storage. We explore the H2O-H2 system at pressures in the range 0-100 GPa with…
Carbon contamination is a significant concern for proton-conducting oxides in the cerate and zirconate family, particularly for BaCeO$_3$. Here, we use first-principles calculations to evaluate carbon stability in SrCeO$_3$, BaCeO$_3$,…
K-Cl is a simple system displaying all four main types of bonding, as it contains (i) metallic potassium, (ii) elemental chlorine made of covalently bonded Cl2 molecules held together by van der Waals forces, and (iii) an archetypal ionic…
Calcium silicate perovskite (CaSiO$_3$) is one of the major mineral components of the lower mantle, but has been the subject of relatively little work compared to the more abundant Mg-based materials. One of the major problems related to…
The low-pressure stabilization of superconducting hydrides with high critical temperatures ($T_c$s) remains a significant challenge, and experimentally verified superconducting hydrides are generally constrained to a limited number of…
Hydrogen-rich hydrides attract great attention due to recent theoretical (1) and then experimental discovery of record high-temperature superconductivity in H3S (Tc = 203 K at 155 GPa (2)). Here we search for stable uranium hydrides at…
We report the formations of fcc and distorted hcp iron-helium compounds with x in FeHex up to 0.13 and 0.48, respectively, based on experiments at 5-54 GPa and ~1000-2820 K. Upon releasing pressure under room temperature, these fcc and…
Using evolutionary crystal structure prediction algorithm USPEX, we identify the compositions and crystal structures of stable compounds in the Fe-S system at pressures in the range 100-400 GPa. We find that at pressures of the Earth's…
Nitrogen hydrides, including ammonia (NH3), hydrazine (N2H4), hydrazoic acid (HN3) and etc, are compounds of great fundamental and applied importance. Their high-pressure behavior is important because of their abundance in giant planets and…
At ambient pressure, sodium, chlorine, and their only known compound NaCl, have well-understood crystal structures and chemical bonding. Sodium is a nearly-free-electron metal with the bcc structure. Chlorine is a molecular crystal,…
Computational searches for new materials are naturally turning from binary systems, to ternary and other multicomponent systems, and beyond. Here, we select the industrially-relevant metals titanium and aluminium and report the results of…
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…
The hydrogen-methane compound (H_2)_4CH_4---or for short H4M---is one of the most promising hydrogen-storage materials. This van der Waals compound is extremely rich in molecular hydrogen: 33.3 mass%, not including the hydrogen bound in…
Many sub-Neptune exoplanets have been believed to be composed of a thick hydrogen-dominated atmosphere and a high-temperature heavier-element-dominant core. From an assumption that there is no chemical reaction between hydrogen and…
Some super Earths and mini Neptunes will likely have thick atmospheres that are not H2-dominated. We have developed a photochemistry-thermochemistry kinetic-transport model for exploring the compositions of thick atmospheres on super Earths…
Recently, it has been shown that under pressure, unexpected and counterintuitive chemical compounds become stable. Laser shock experiments (A. Rode, unpublished) on alumina (Al2O3) have shown non-equilibrium decomposition of alumina with…
Layered, hexagonal crystal structures, like zeta and eta phases, play an important role in ultra-high temperature ceramics, often significantly increasing toughness of carbide composites. Despite their importance open questions remain about…
Carbon at extreme conditions is the focus of intensive scientific inquiry due to its importance for applications in inertial confinement fusion experiments and for understanding the interior structure of carbon-rich exoplanets. The extreme…