Sökning: "Hybrid density functional"

Visar resultat 1 - 5 av 62 avhandlingar innehållade orden Hybrid density functional.

  1. 1. Atomistic modelling of functional solid oxides for industrial applications : Density Functional Theory, hybrid functional and GW-based studies

    Författare :Cecilia Århammar; Rajeev Ahuja; Steven Louie; KTH; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; density functional theory; oxides; GW; Condensed matter physics; Kondenserade materiens fysik; Magnetism; Magnetism; Defects and diffusion; Defekter och diffusion;

    Sammanfattning : In this Thesis a set of functional solid oxides for industrial applications have been addressed by first principles and thermodynamical modelling. More specificially, measurable quantities such as Gibbs free energy, geometry and electronic structure have been calculated and compared when possible with experimental data. LÄS MER

  3. 2. First-Principles Studies of Materials Properties : Pressure-Induced Phase Transitions & Functional Materials

    Författare :Thanayut Kaewmaraya; Rajeev Ahuja; Scheicher Ralph; Naurang Saini; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Density functional theory; Pressure-induced phase transitions; Ab-initio molecular dynamic; hybrid functional; Ab-initio random structure searching; Phase change material; Physics with spec. in Atomic; Molecular and Condensed Matter Physics; Fysik med inriktning mot atom- molekyl- och kondenserande materiens fysik;

    Sammanfattning : This thesis presents the first-principles studies of materials properties within the framework of the density functional theory (DFT). The thesis constitutes three main parts, i. e., pressure-induced phase transitions in solids, data-storage and clean-energy materials. LÄS MER

  4. 3. Oxygen Storage Chemistry of Nanoceria

    Författare :Dou Du; Kersti Hermansson; Peter Broqvist; Pavlin D. Mitev; Joachim Paier; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Nanoceria; Density Functional Theory; Hybrid Functional; Oxygen Storage Capacity.; Kemi med inriktning mot materialkemi; Chemistry with specialization in Materials Chemistry;

    Sammanfattning : The versatile redox chemistry of ceria (CeO2) originates from its Ce4f electron, which plays the key role in changing the oxidation state of Ce between +IV and +III. Ceria is, among other things, a material that can act as a powerful oxygen buffer with a high oxygen storage capacity (OSC). LÄS MER

  5. 4. Vibrational and Structural Characterisation in Two Perovskite Challenges: A Density Functional Theory Study

    Författare :Erik Jedvik Granhed; Chalmers tekniska högskola; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; phonon; chemical expansion; materials modelling; oxyhydride; polaron; vibrational analysis; BaTiO3; BaZrO3; anti-ferrodistortive; density functional theory;

    Sammanfattning : The modelling of perovskites using density functional theory (DFT) can sometimes be a challenge with many different states very close in energy. In particular, the tilting of the inscribed octahedron, as well as the formation of electron polarons, leads to states with energy differences in the meV range. LÄS MER

  7. 5. Modeling hybrid halide perovskites for solar cell applications : Simulations of electronic structure and X-ray spectroscopy

    Författare :Cody M. Sterling; Michael Odelius; Alison B. Walker; Stockholms universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Solar cells; perovskites; computational chemistry; simulations; electronic structure; density functional theory; X-ray spectroscopy; kemisk fysik; Chemical Physics;

    Sammanfattning : Over the past 13 years, perovskites have become a very promising candidate in the search for cheap and effective photovoltaic materials for solar cells.  Perovskite solar cell power conversion efficiency has increased from 3. LÄS MER