Experimental evidence of strong phonon scattering in isotopical disordered systems: The case of LiH_xD_{1-x} crystals

The observation of the local - mode vibration, the two - mode behavior of the LO phonons at large isotope concentration, as well as large line broadening in LIH - D mixed crystals directly evidence strong additional phonon scattering due to the isotope - induced disorder.Comment: 9 pages, 4 figure

Domestication as Enskilment : Harnessing Reindeer in Arctic Siberia

Acknowledgements Funding for this project was provided by the Wenner-Gren Foundation (SFR1725) to R. Losey, the JPI HUMANOR project (ESRC ES/M011054/1) to D. Anderson, ERC GRETPOL to D. Arzyutov, and the Russian Foundation for Basic Research to N.Fedorova (18-09-40011). The authors wish to express their gratitude to the Nenets families, the Okotettos and Yaungads, who hosted us during our stay in Iamal, which is greatly appreciated. Special thanks are also offered to the staff of Iamal-Nenets Autonomous District, and the staff of the Iamal-Nenets Regional Museum and Exhibition Complex of I.S. Shemanovskii, Peter the Great Museum of Anthropology and Ethnography, and British Museum for providing access to their collections.Peer reviewedPostprin

Electronic structure and optical properties of lightweight metal hydrides

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.Comment: 13 pages, 10 figure