Strong electron-phonon and band structure effects in the optical properties of high pressure metallic hydrogen

Abstract

Characterization of the first ever laboratory produced metallic hydrogen sample relies on measurements of optical spectra. Here we present first-principles calculations of the reflectivity of hydrogen between 400 and 600 GPa in the $\mathrm{I}{4}_1/amd$ crystal structure, the one predicted at these pressures, based on both time-dependent density functional and Eliashberg theories, thus, covering the optical properties from the infrared to the ultraviolet regimes. Our results show that atomic hydrogen displays an interband plasmon at around 6 eV that abruptly suppresses the reflectivity, while the large superconducting gap energy yields a sharp decrease of the reflectivity in the infrared region approximately at 120 meV. The experimentally estimated electronic scattering rates in the 0.7-3 eV range are in agreement with our theoretical estimations, which show that the huge electron-phonon interaction of the system dominates the electronic scattering in this energy range. The remarkable features in the optical spectra predicted here encourage to extend the existing optical measurements to the infrared and ultraviolet regions.

References in corpus (10)

• Quantum ESPRESSO: a modular and open-source software project for quantum simulations of materials
• Observation of the Wigner-Huntington Transition to Solid Metallic Hydrogen
• Dissociation of high-pressure solid molecular hydrogen: Quantum Monte Carlo and anharmonic vibrational study
• The Melting Line of Hydrogen at High Pressures
• Spectroscopy of H${}_3$S: evidence of a new energy scale for superconductivity
• Anharmonic effects in atomic hydrogen: superconductivity and lattice dynamical stability
• Comment on "Observation of the Wigner-Huntington transition to metallic hydrogen"
• Comments on the claimed observation of the Wigner-Huntington Transition to Metallic Hydrogen
• Comment on: Observation of the Wigner-Huntington transition to metallic hydrogen
• Comment on Observation of the Wigner-Huntington transition to metallic hydrogen

Cited by in corpus (9)

• A Perspective on Conventional High-Temperature Superconductors at High Pressure: Methods and Materials
• Quantum phase diagram of high-pressure hydrogen
• Strong Anharmonic and Quantum Effects in Pm-3n AlH3 Under High Pressure: A First-Principles Study
• Public Debate on Metallic Hydrogen to Boost High Pressure Research
• Detecting superconductivity in the high pressure hydrides and metallic hydrogen from optical properties
• Ab initio investigation on the experimental observation of metallic hydrogen
• Atomization of correlated molecular-hydrogen chain: A fully microscopic Variational Monte-Carlo solution
• Observed Metallization of Hydrogen Interpreted as a Band Structure Effect
• Comment on: Observation of a first order phase transition to metal hydrogen near 425 GPa