Strong Anharmonic and Quantum Effects in Pm-3n AlH3 Under High Pressure: A First-Principles Study

Abstract

Motivated by the absence of experimental superconductivity in the metallic Pm-3n phase of AlH3 despite the predictions, we reanalyze its vibrational and superconducting properties at pressures above 99 GPa making use of first-principles techniques. In our calculations based on the self-consistent harmonic approximation method that treats anharmonicity beyond perturbation theory, we predict a strong anharmonic correction to the phonon spectra and demonstrate that the superconducting critical temperatures predicted in previous calculations based on the harmonic approximation are strongly suppressed by anharmonicity. The electron-phonon coupling concentrates on the lowest-energy hydrogen-character optical modes at the X point of the Brillouin zone. As a consequence of the strong anharmonic enhancement of their frequency, the electron-phonon coupling is suppressed by at least a 30%. The suppression in λ makes Tc smaller than 4.2 K above 120 GPa, which is well consistent with the experimental evidence. Our results underline that metal hydrides with hydrogen atoms in interstitial sites are subject to huge anharmonic effects.

References in corpus (30)

• Quantum ESPRESSO: a modular and open-source software project for quantum simulations of materials
• Phonons and related properties of extended systems from density-functional perturbation theory
• Advanced capabilities for materials modelling with Quantum ESPRESSO
• Conventional superconductivity at 203 K at high pressures
• Superconductivity at 250 K in lanthanum hydride under high pressures
• Evidence for superconductivity above 260 K in lanthanum superhydride at megabar pressures
• Superconductive "sodalite"-like clathrate calcium hydride at high pressures
• Observation of the Wigner-Huntington Transition to Solid Metallic Hydrogen
• A Perspective on Conventional High-Temperature Superconductors at High Pressure: Methods and Materials
• Hydrogen sulphide at high pressure: a strongly-anharmonic phonon-mediated superconductor
• Anomalous high-temperature superconductivity in YH${}_6$
• Anharmonic free energies and phonon dispersions from the stochastic self-consistent harmonic approximation: application to platinum and palladium hydrides
• Quantum Crystal Structure in the 250 K Superconducting Lanthanum Hydride
• Pressure-induced decomposition of solid hydrogen sulfide
• Quantum Hydrogen-Bond Symmetrization and High-Temperature Superconductivity in Hydrogen Sulfide
• First-Principles Theory of Anharmonicity and the Inverse Isotope Effect in Superconducting Palladium-Hydride Compounds
• Superconductivity to 262 kelvin via catalyzed hydrogenation of yttrium at high pressures
• Superconducting hydrides under pressure
• Second order structural phase transitions, free energy curvature, and temperature-dependent anharmonic phonons in the self-consistent harmonic approximation: theory and stochastic implementation
• Tellurium Hydrides at High Pressures: High-temperature Superconductors
• Metallization of Magnesium Polyhydrides Under Pressure
• Pressure and stress tensor of complex anharmonic crystals within the stochastic self-consistent harmonic approximation
• Anharmonic effects in atomic hydrogen: superconductivity and lattice dynamical stability
• Phase Diagram and High-Temperature Superconductivity of Compressed Selenium Hydrides
• Predicted formation of superconducting platinum-hydride crystals under pressure in the presence of molecular hydrogen
• Superconductivity up to 243 K in yttrium hydrides under high pressure
• Giant anharmonicity suppresses superconductivity in AlH${}_3$ under pressure
• Time-Dependent Self Consistent Harmonic Approximation: Anharmonic nuclear quantum dynamics and time correlation functions
• High-pressure phase diagram of hydrogen and deuterium sulfides from first principles: structural and vibrational properties including quantum and anharmonic effects
• Strong electron-phonon and band structure effects in the optical properties of high pressure metallic hydrogen

Cited by in corpus (13)

• Strong correlation between bonding network and critical temperature in hydrogen-based superconductors
• Tuning Chemical Precompression: Theoretical Design and Crystal Chemistry of Novel Hydrides in the Quest for Warm and Light Superconductivity at Ambient Pressures
• Superconductivity in Li8Au electride
• High-temperature superconductivity in hydrides
• Al-Based Few-Hydrogen Metal-Bonded Perovskite High-$T_c$ Superconductor Al${}_4$H up to 54 K under Atmospheric Pressure
• Quantum anharmonic enhancement of superconductivity in $P{6}_3/mmc$ ScH${}_6$ at high pressures: a first-principles study
• Ab initio study of metastable occupation of tetrahedral sites in palladium hydrides and its impact on superconductivity
• Universal Fermi velocity in highly compressed hydride superconductors
• Superconducting hydrides on a quantum landscape
• Quantifying the nonadiabaticity strength constant in recently discovered highly-compressed superconductors
• Comparison of highly-compressed C2/m-SnH12 superhydride with conventional superconductors
• Fermi-liquid nonadiabatic highly-compressed cesium iodide superconductor
• Structural and superconducting parameters of highly compressed sulfur