Melting conditions and entropies of superionic water ice: Free-energy calculations based on hybrid solid/liquid reference systems

Article Multidisciplinary Sciences

Superionic iron alloys and their seismic velocities in Earth's inner core

Yu He et al.

Summary: Earth's inner core may contain light elements such as hydrogen, oxygen and carbon, which under IC conditions may transform into a superionic state, leading to a decrease in seismic velocities and explaining the soft structure of the IC.

NATURE (2022)

Add to Collection

Article Multidisciplinary Sciences

Dynamic compression of water to conditions in ice giant interiors

A. E. Gleason et al.

Summary: Recent discoveries of water-rich Neptune-like exoplanets require a better understanding of the phase diagram of H2O under pressure-temperature conditions relevant to their interiors. This study presents evidence of a body-centered cubic (BCC) structured ice, ice XIX, at extreme pressure and temperature conditions, using X-ray diffraction. The discovery suggests increased electrical conductivity and the generation of multipolar magnetic fields in ice giant planets.

SCIENTIFIC REPORTS (2022)

Add to Collection

Article Computer Science, Interdisciplinary Applications

LAMMPS-a flexible simulation tool for particle-based materials modeling at the atomic, meso, and continuum scales

Aidan P. Thompson et al.

Summary: LAMMPS, a classical molecular dynamics simulator released as an open source code in 2004, has gained popularity for its wide variety of particle interaction models, platform compatibility, and user control over simulation details. With contributions from numerous developers, it has grown from 50,000 lines of code to a million today, showcasing new capabilities like dynamic load balancing and quantum-accuracy machine learning interatomic potentials.

COMPUTER PHYSICS COMMUNICATIONS (2022)

Add to Collection

Article Materials Science, Multidisciplinary

Non-equilibrium free-energy calculation of phase-boundaries using LAMMPS

Samuel Cajahuaringa et al.

Summary: This article presents a guide to computing the phase boundaries of classical systems using the dynamic Clausius-Clapeyron integration (dCCI) method in the LAMMPS code. The advantage of the dCCI method is its ability to provide coexistence curves spanning a wide range of thermodynamic states in relatively short non-equilibrium simulations. The article describes the state-of-the-art non-equilibrium free-energy methods and presents the implementation of the dCCI method in LAMMPS, along with source code, scripts, and auxiliary files. An illustrative example of determining the phase diagram of silicon is provided.

COMPUTATIONAL MATERIALS SCIENCE (2022)

Add to Collection

Article Multidisciplinary Sciences

Thermodynamics of high-pressure ice phases explored with atomistic simulations

Aleks Reinhardt et al.

Summary: Through large-scale molecular dynamics simulations, we studied the phase behavior of high-pressure ice. The results indicate that some ice phases with a body-centered cubic oxygen lattice belong to the same thermodynamic phase under different conditions, while superionic ice has a first-order phase boundary. Furthermore, at higher pressures, the activation barrier for ice transformation gradually increases. Our study reveals peculiar solid-solid transition mechanisms in high-pressure ice phases.

NATURE COMMUNICATIONS (2022)

Add to Collection

Article Multidisciplinary Sciences

Plastic deformation of superionic water ices

Filipe Matusalem et al.

Summary: There has been a growing interest in the mechanical properties of superionic (SI) phases of water ice, which play a potential role in the geophysical properties of Neptune and Uranus. This study assessed the mechanical response of high-pressure/temperature solid phases of water using density functional theory calculations and machine learning techniques. The results indicate that SI ices are highly ductile and the plastic flow of the internal icy layers in Neptune and Uranus may be significantly faster than previously foreseen.

PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA (2022)

Add to Collection

Review Materials Science, Multidisciplinary

Deep potentials for materials science

Tongqi Wen et al.

Summary: This paper introduces the application of deep potential (DP) methods in computational materials science, including the theoretical basis, development and usage, as well as the application in various materials systems. Additionally, it discusses the accuracy and efficiency of DPs compared to ab initio methods and empirical potentials.

MATERIALS FUTURES (2022)

Add to Collection

Article Multidisciplinary Sciences

Fluid-like elastic response of superionic NH3 in Uranus and Neptune

Tomoaki Kimura et al.

Summary: The non-dipolar magnetic fields at Uranus and Neptune may result from the unique geometry of their icy mantles, potentially stabilized by the presence of superionic H2O and NH3. Experimental measurements on NH3 show changes in its properties under specific conditions, suggesting potential implications for understanding the internal structure of these planets.

PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA (2021)

Add to Collection

Article Physics, Multidisciplinary

Phase behaviours of superionic water at planetary conditions

Bingqing Cheng et al.

Summary: The study predicts the phase behavior of water inside ice giant planets using machine learning and free-energy methods, revealing that most water may be superionic. The researchers also overcome the difficulty of experimentally or theoretically probing the thermodynamic and transport properties of superionic water by utilizing new methods. They predict the stability of different superionic phases, phase boundaries, and successfully resolve the fractions of insulating ice, different superionic phases, and liquid water inside ice giants.

NATURE PHYSICS (2021)

Add to Collection

Article Computer Science, Interdisciplinary Applications