Crystal Structures and Properties of Iron Hydrides at High Pressure

Abstract

Evolutionary algorithms and the particle swarm optimization method have been used to predict stable and metastable high hydrides of iron between 150-300 GPa that have not been discussed in previous studies. Cmca FeH5, Pmma FeH6 and P2/c FeH6 contain hydrogenic lattices that result from slight distortions of the previously predicted I4/mmm FeH5 and Cmmm FeH6 structures. Density functional theory calculations show that neither the I4/mmm nor the Cmca symmetry FeH5 phases are superconducting. A P1 symmetry FeH7 phase, which is found to be dynamically stable at 200 and 300 GPa, adds another member to the set of predicted nonmetallic transition metal hydrides under pressure. Two metastable phases of FeH${}_8$ are found, and the preferred structure at 300 GPa contains a unique 1-dimensional hydrogenic lattice.

arXiv comment24 pages, 7 figures

References in corpus (17)

• Quantum ESPRESSO: a modular and open-source software project for quantum simulations of materials
• CALYPSO: a method for crystal structure prediction
• Conventional superconductivity at 203 K at high pressures
• Evidence for superconductivity above 260 K in lanthanum superhydride at megabar pressures
• EPW: Electron-phonon coupling, transport and superconducting properties using maximally localized Wannier functions
• Superconductive "sodalite"-like clathrate calcium hydride at high pressures
• Phonon-phonon interactions in transition metals
• High-Temperature Superconductivity in Atomic Metallic Hydrogen
• Tellurium Hydrides at High Pressures: High-temperature Superconductors
• Fe-C and Fe-H systems at pressures of the Earth's inner core
• Rubidium Polyhydrides Under Pressure: Emergence of the Linear H3- Anion
• Superconductivity above 100 K in PH3 at high pressures
• Iron superhydrides FeH5 and FeH6: stability, electronic properties and superconductivity
• The Search for Superconductivity in High Pressure Hydrides
• Superconductivity at 215 K in lanthanum hydride at high pressures
• Absence of superconductivity in iron polyhydrides at high pressures
• Origins of low- and high-pressure discontinuities of $T_c$ in niobium

Cited by in corpus (7)

• A Perspective on Conventional High-Temperature Superconductors at High Pressure: Methods and Materials
• Superconducting hydrides under pressure
• High-Temperature Superconductivity in Alkaline and Rare Earth Polyhydrides at High Pressure: A Theoretical Perspective
• Predicting novel superconducting hydrides using machine learning approaches
• Designing High-Tc Superconductors with BCS-inspired Screening, Density Functional Theory and Deep-learning
• The Search for Superconductivity in High Pressure Hydrides
• Machine Learning-Driven Structure Prediction for Iron Hydrides