Related papers: Metastable Carbon at Extreme Conditions
Molecular hydrogen was pressurized in a diamond anvil cell at temperatures between 5 and 83 K. At a sufficiently high pressure, estimated to be between 477 to 491 GPa, hydrogen became metallic, determined by its reflectance in the near…
Carbon exhibits both a layered ground state structure that produces two-dimensional (2D) nanosheets and a non-layered diamond structure created under high pressure conditions. Motivated by this metastability relationship, we revisit the…
Carbonate minerals are important in Earth's system sciences and have been found on Mars and in meteorites and asteroids, highlighting the importance of impacts in planetary processes. While extensively studied under static compression, the…
Granular media jam into a panoply of metastable states. The way in which these states are achieved depends on the nature of local and global constraints on grains; here we investigate this issue by means of a non-equilibrium stochastic…
Pressure is a unique tool to tune the interplay between structural, electronic and magnetic interactions. It leads to remarkable properties of materials such as recent temperature records in superconductivity. Advanced magnetic measurements…
Ascertaining rocky exoplanets dynamic evolution requires better understanding of key internal thermophysical processes that shaped their geological surfaces, heat fluxes, volatiles and atmospheric content. New high-pressure experiments on…
Surfaces of natural diamonds etched in high-pressure experiments in H2O, CO2 and H2O-NaCl fluids were investigated using Atomic Force Microscopy. Partial dissolution of the crystals produced several types of surface features including the…
The high-pressure melting curves of metals provide simple and useful tests for theories of melting, as well as important constraints for the modeling of planetary interiors. Here, we present an experimental technique that reveals the latent…
We present large scale electronic structure based molecular dynamics simulations of liquid methane at planetary conditions. In particular, we address the controversy of whether or not the interior of Uranus and Neptune consists of diamond.…
We investigate the phase behavior of a single-component system in 3 dimensions with spherically-symmetric, pairwise-additive, soft-core interactions with an attractive well at a long distance, a repulsive soft-core shoulder at an…
Processes involving severe plastic deformations (SPD) and phase transformations and chemical reactions (PTs/CRs) under high pressures are widespread for obtaining new nanostructured phases and their processing, mechanochemical synthesis,…
Diamond holds significant promise for a wide range of applications due to its exceptional physicochemical properties. Investigating the controlled diamond preparation from nanocarbon precursors with varying dimensions is crucial to optimize…
The behaviour of partially ionized hot compressed matter is critical to the study of planetary interiors as well as for nuclear fusion studies. A recent quantum study of carbon in the 10-70 Gbar range and at a temperature of 100 eV used…
By applying a genetic algorithm in a cascade approach of increasing accuracy, we calculate the composition and structure of MgMOx clusters at realistic temperatures and oxygen pressures. The stable and metastable systems are identified by…
The shock strength dependent formation of diamond represents one of the most intriguing questions in graphite research. Using ab initio DFT-trained carbon GNN model, we observe a strength-dependent graphite transition under shock. The poor…
We present an ab-initio study of boron nitride as well as carbon allotropes. Their relative thermodynamic stabilities and structural phase transitions from low- to high-density phases are investigated. Pressure-temperature phase diagrams…
The iron-sulfur system is important for planetary interiors and is intensely studied, particularly for better understanding of the cores of Mars and Earth. Yet, there is a paradox about high-pressure stability of FeS: ab initio global…
We examine the conditions that give rise to metastable, persistent currents in a trapped Bose-Einstein condensate. A necessary condition for the stability of persistent currents is that the trapping potential is not a monotonically…
We show that a system of particles interacting through the exp-6 pair potential, commonly used to describe effective interatomic forces under high compression, exhibits anomalous melting features such as reentrant melting and a rich solid…
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,…