Browsing by Author "Mastrikov, Yuri"

Filter results by typing the first few letters
Now showing 1 - 1 of 1
  • Thumbnail Image
    ItemOpen Access
    First-principles calculations of LaMnO3 surface reactivity
    (2008) Mastrikov, Yuri; Maier, Joachim (Prof. Dr.)
    The main aim of this Thesis is to model elementary processes at the Solid Oxide Fuel Cell (SOFC) cathode on the atomic level. As a model cathode material we use LaMnO3. For this purpose we have chosen the Generalized Gradient Approximation (GGA) method within the Density Functional Theory (DFT) as implemented into the VASP computer code.. One of the main reasons to choose this code is its powerful structure optimisation algorithm. As it is demonstrated in the Thesis, despite certain flaws of the DFT method, it gives very reasonable structural and energetic parameters for such strongly correlated materials as LaMnO3. We calculated the atomic and electronic structure of the perfect LaMnO3 and of its bare surfaces; we modelled adsorbed oxygen on the MnO2-terminated surface, as well as O vacancies in the bulk and on the (001) surface. Along with static properties, we also calculated adsorbed O and O vacancy migration energies, LaMnO3 cohesive energy and surface formation energies. The electronic density distribution was analysed by means of the electron difference maps and the effective atomic charges calculated by means of the topological (Bader) analysis. Special attention was paid to the energetics and charge redistribution upon adsorption of O atoms and O2 molecules on the LaMnO3 (001) surface.