Ab initio study of the structural, vibrational and optical properties of potential parent structures of nitrogen-doped lutetium hydride

Abstract

The recent report of near-ambient conditions superconductivity in a nitrogen-doped lutetium hydride has inspired a large number of experimental studies with contradictory results. We model from first principles the physical properties of the possible parent structures of the reported superconductor, LuH${}_2$ and LuH${}_3$. We show that only the phonon band structure of LuH${}_3$ can explain the reported Raman spectra due to the presence of hydrogens at the interstitial octahedral sites. However, this structure is stabilized by anharmonicity only above 6 GPa. We find that the intriguing color change with pressure in the reported superconductor is consistent with the optical properties of LuH${}_2$, which are determined by the presence of an undamped interband plasmon. The plasmon blue-shifts with pressure and modifies the color of the sample without requiring any structural phase transition. Our findings suggest that the main component in the experiments is LuH${}_2$ with some extra hydrogen atoms at octahedral sites. None of LuH${}_2$ and LuH${}_3$ superconduct at high temperatures.

References in corpus (31)

• 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
• CALYPSO: a method for crystal structure prediction
• Crystal Structure Prediction via Particle Swarm Optimization
• Conventional superconductivity at 203 K at high pressures
• The PseudoDojo: Training and grading a 85 element optimized norm-conserving pseudopotential table
• Quantum ESPRESSO toward the exascale
• Wannier90 as a community code: new features and applications
• Superconductivity at 250 K in lanthanum hydride under high pressures
• Evidence for superconductivity above 260 K in lanthanum superhydride at megabar pressures
• Ab initio calculation of the anomalous Hall conductivity by Wannier interpolation
• 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
• Spectral and Fermi surface properties from Wannier interpolation
• First-Principles Theory of Anharmonicity and the Inverse Isotope Effect in Superconducting Palladium-Hydride Compounds
• Superconducting hydrides under pressure
• Towards high-throughput superconductor discovery via machine learning
• The Stochastic Self-Consistent Harmonic Approximation: Calculating Vibrational Properties of Materials with Full Quantum and Anharmonic Effects
• Second order structural phase transitions, free energy curvature, and temperature-dependent anharmonic phonons in the self-consistent harmonic approximation: theory and stochastic implementation
• Pressure and stress tensor of complex anharmonic crystals within the stochastic self-consistent harmonic approximation
• Hubbard-corrected density functional perturbation theory with ultrasoft pseudopotentials
• Time-Dependent Self Consistent Harmonic Approximation: Anharmonic nuclear quantum dynamics and time correlation functions
• Pressure-induced color change in the lutetium dihydride LuH2
• Pressure induced color change and evolution of metallic behavior in nitrogen-doped lutetium hydride
• Leading components and pressure-induced color changes in N-doped lutetium hydride
• Photorealistic modelling of metals from first principles
• Ab initio study of metastable occupation of tetrahedral sites in palladium hydrides and its impact on superconductivity
• Transformation of hexagonal Lu to cubic LuH${}_{2+x}$ single-crystalline films
• Including many-body effects into the Wannier-interpolated quadratic photoresponse tensor
• Drude weight in systems with open boundary conditions

Cited by in corpus (8)

• Observation of non-superconducting phase changes in LuH${}_{2\pm \text{x}}$N${}_y$
• Temperature and quantum anharmonic lattice effects on stability and superconductivity in lutetium trihydride
• Assessing the feasibility of near-ambient conditions superconductivity in the Lu-N-H system
• Anatomy of the band structure of the newest apparent near-ambient superconductor LuH${}_{3-x}$N${}_x$
• Unveiling a Novel Metal-to-Metal Transition in LuH2: Critically Challenging Superconductivity Claims in Lutetium Hydrides
• Evidence of Molecular Hydrogen in the N-doped LuH3 System: a Possible Path to Superconductivity?
• Superconductivity in barium hydrides via incorporation of light elements
• Ternary Phase Diagram of Nitrogen Doped Lutetium Hydrides