Related papers: Metastable Carbon at Extreme Conditions
The transformation pathways of carbon at high pressures are of broad interest for synthesis of novel materials and for revealing the Earth's geological history. We have applied large plastic shear on graphite in rotational anvils to form…
In this paper theoretical and statistical/experimental criteria for determining the nanoscale strength of materials are proposed. In particular, quantized criteria in fracture mechanics, dynamic fracture mechanics and fatigue, as well as an…
Based on crystal chemistry considerations and quantum density functional theory ground state calculations, rhombohedral rh-C3 and hexagonal h-C6 carbon allotropes are proposed and energetically calculated as new stable ultra-hard phases…
High-pressure superconductivity in a rare-earth doped Ca0.86Pr0.14Fe2As2 single crystalline sample has been studied up to 12 GPa and temperatures down to 11 K using designer diamond anvil cell under a quasi-hydrostatic pressure medium. The…
Manganese, in the a-Mn structure, has been studied using synchrotron powder x-ray diffraction in a diamond anvil cell up to 220 GPa at room temperature combined with density functional calculations (DFT). The experiment reveals an extended…
We present tight-binding molecular dynamics simulations of the structural modifications that result from the "thermal spike" that occurs during the passage of a heavy fast ion through a thin diamond or amorphous carbon layer, and the…
Motivated by the recent discovery of near-room temperature superconductivity in high-pressure superhydrides, we investigate from first-principles the high-pressure superconducting phase diagram of the ternary Ca-B-H system, using ab-initio…
As titanium is a highly utilized metal for structural light-weighting, its phases, transformation pathways (transition states), and structures have scientific and industrial importance. Impurities, pressure, and temperature control the…
Boron forms a wide variety of compounds with alkaline earth elements due to its unique bonding characteristics. Among these, binary compounds of Be and B display particularly rich structural diversity, attributed to the small atomic size of…
In order to probe the mechanism of solid-solid phase transformations, we have applied ultrafast shock wave compression (120 picosecond duration) and ultrashort (130 femtosecond) x-ray diffraction at the Linac Coherent Light Source (LCLS) to…
Colloidal particles are often seen as big atoms that can be directly observed in real space. They are therefore playing an increasingly important role as model systems to study processes of interest in condensed matter physics such as…
Astrophysical measurements have shown that some stars have sufficiently high carbon-to-oxygen ratios such that the planets they host would be mainly composed of carbides instead of silicates. We studied the behavior of silicon carbide in…
We calculate analytically the phase diagram of a two-dimensional square crystal and its wrapped version with defects under external homogeneous stress as a function of temperature using a simple elastic lattice model that allows for defect…
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…
MAB phases (MABs) are atomically-thin laminates of ceramic/metallic-like layers, having made a breakthrough in the development of 2D materials. Though theoretically offering a vast chemical and phase space, relatively few MABs have yet been…
By employing $ab$ $initio$ molecular dynamics simulations at constant pressure, we investigated behavior of amorphous carbon dioxide between 0-100 GPa and 200-500 K and found several new amorphous forms. We focused on evolution of the…
We show by means of molecular dynamics simulations that graphene is an excellent coating for diamond. The transformation of diamond to amorphous carbon while sliding under pressure can be prevented by having at least two graphene layers…
A thorough in situ characterization of materials at extreme conditions is challenging, and computational tools such as crystal structural search methods in combination with ab initio calculations are widely used to guide experiments by…
We experimentally and theoretically study the peak fraction of a Bose-Einstein condensate loaded into a cubic optical lattice as the lattice potential depth and entropy per particle are varied. This system is well-described by the…
We study the leptonic decay of charged pions in a compact star environment. Considering leptons as a degenerated Fermi system, pions are tightly constrained to decay into these particles because their Fermi levels are occupied. Thus, pion…