Electronic structure and optical properties of lightweight metal hydrides

Abstract

We study the electronic structures and dielectric functions of the simple hydrides LiH, NaH, MgH2 and AlH3, and the complex hydrides Li3AlH6, Na3AlH6, LiAlH4, NaAlH4 and Mg(AlH4)2, using first principles density functional theory and GW calculations. All these compounds are large gap insulators with GW single particle band gaps varying from 3.5 eV in AlH3 to 6.5 eV in the MAlH4 compounds. The valence bands are dominated by the hydrogen atoms, whereas the conduction bands have mixed contributions from the hydrogens and the metal cations. The electronic structure of the aluminium compounds is determined mainly by aluminium hydride complexes and their mutual interactions. Despite considerable differences between the band structures and the band gaps of the various compounds, their optical responses are qualitatively similar. In most of the spectra the optical absorption rises sharply above 6 eV and has a strong peak around 8 eV. The quantitative differences in the optical spectra are interpreted in terms of the structure and the electronic structure of the compounds.

arXiv comment13 pages, 10 figures

References in corpus (10)

• The GW method
• Quasiparticle Self-Consistent GW Theory
• Implementation of an all-electron GW approximation based on the PAW method without plasmon pole approximation: application to Si, SiC, AlAs, InAs, NaH and KH
• Pressure-induced structural transitions in MgH${}_2$
• The GW space-time method for the self-energy of large systems
• Optical properties of MgH2 measured in situ in a novel gas cell for ellipsometry/spectrophotometry
• Electronic Structure of the Complex Hydride NaAlH4
• Ab initio study of magnesium alanate, Mg(AlH4)2
• Pressure-Induced Simultaneous Metal-Insulator and Structural-Phase Transitions in LiH: a Quasiparticle Study
• Ab-initio prediction of the electronic and optical excitations in polythiophene: isolated chains versus bulk polymer

Cited by in corpus (19)

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• Improved Band Gaps and Structural Properties from Wannier-Fermi-Löwdin Self-Interaction Corrections for Periodic Systems
• The Search for Superconductivity in High Pressure Hydrides
• Tunable Hydrogen Storage in Magnesium - Transition Metal Compounds
• First-principles study of the optical properties of MgxTi(1-x)H2
• First principles modelling of magnesium titanium hydrides
• Electronic and Vibrational Properties of gamma-AlH3
• Decomposition mechanism and the effects of metal additives on the kinetics of lithium alanate
• Variational Excitations in Real Solids: Optical Gaps and Insights into Many-Body Perturbation Theory
• Screened extended Koopmans' theorem: photoemission at weak and strong correlation
• LiH as a Li${}^{+}$ and H${}^{-}$ ion provider
• A model for the formation energies of alanates and boranates
• Amphoteric behavior of hydrogen (H+1and H-1) in complex hydrides from van der Waals interaction included ab-initio calculation
• A first-principles study of superconductivity on RbH by doping without applied pressure
• The Li-F-H Ternary System at High Pressures
• Impact of Exchange-Correlation Functionals on Predictions of Phonon Hydrodynamics: A Study of Fluorides, Chlorides, and Hydrides
• On the breakdown of the Born-Oppenheimer approximation in LiH and LiD
• BCS superconductivity in ionic hydrides using chemical capacitor setup