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MP: Fachverband Theoretische und Mathematische Grundlagen der Physik

MP 13: Poster (permanent Mo-Do)

MP 13.3: Poster

Dienstag, 18. März 2014, 08:00–18:00, SPA Foyer

Ab initio calculations of f-element compounds and solids with DFT+U method — •George Beridze¹, Ariadna Blanca-Romero^{1, 2}, Yan Li¹, and Piotr Kowalski¹ — ¹Institute of Energy and Climate Research, Nuclear Waste Management and Reactor Safety, Forschungszentrum J\"ulich, Wilhelm-Johnen-Straße, 52428, J\"ulich, Germany — ²Department of Chemistry, Imperial College London, London, United Kingdom

Safe storage of nuclear waste is a tough challenge facing today's society. It requires a deep understanding of chemistry and physics of complicated radionuclide-bearing systems. Nowadays, computational modelling is used alongside experiments to simulate behavior of these complex materials. Because of strong correlations, lanthanide- and actinide-bearing systems are not always well described by Density Functional Theory (DFT), which is the only computationally affordable method. We show results of DFT+U studies of different f-element-bearing oxides, phosphates, halogenides and zirconates that are of interest for nuclear waste management. We obtained the best description of these materials with the Hubbard U (and J) parameters derived for each cation and material using linear response method. Predicted structures of many of modelled materials agree surprisingly well with the measured ionic positions and lattice parameters. This is not seen when standard DFT methods are used. Our results indicate that simple modifications of DFT such as DFT+U, with properly estimated U parameter can successfully be used in computation of strongly correlated materials.