Sökning: "Ab initio lattice dynamics"

Visar resultat 6 - 10 av 18 avhandlingar innehållade orden Ab initio lattice dynamics.

  1. 6. Materials Design from ab initio Calculations

    Författare :Sa Li; Börje Johansson; Rajeev Ahuja; Gilles Hug; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Physics; DFT; MAX; Optics; phase transition; phonon; EOS; Fysik; Physics; Fysik;

    Sammanfattning : This thesis presents a theoretical study of bulk materials using ab initio methods based on the density functional theory (DFT).Crystallographic structural phase transformations and phase stability for 5f-dioxides, ABO3 perovskites, and ABO4 compounds have been extensively studied. LÄS MER

  3. 7. Effects of disorder in metallic systems from First-Principles calculations

    Författare :Christian Asker; Igor Abrikosov; Jörg Neugebauer; Linköpings universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; Iron; Nickel; Magnesium; Manganese; Molybdenum; Zirconium; Elastic Constants; High pressure; Earth s core; Density-functional theory; Ab-initio; First-Principles; Core-level shifts; Molecular Dynamics; Phonons; Dynamical Instability; Condensed matter physics; Kondenserade materiens fysik; Computational physics; Beräkningsfysik;

    Sammanfattning : In this thesis, quantum-mechanical calculations within density-functional theory on metallic systems are presented. The overarching goal has been to investigate effects of disorder. In particular, one of the properties investigated is the bindingenergy shifts for core electrons in binary alloys using different theoretical methods. LÄS MER

  4. 8. Theoretical studies of lattice- and spin-polarons

    Författare :Nina Bondarenko; Olle Eriksson; Natalia Skorodumova; Manuel Pereiro; Maria Roser Valenti Vall; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Polaron; Nonlinear Schrödinger Equation; Nonlocality; Solitons; Integrable systems; Quantum field theory low energy ; Electron-phonon interaction; Density functional theory; Electronic structure of atoms and molecules; Spin-polaron; Langevin equation; Transport properties; Hubbard model; Heisenberg lattice; Physics with spec. in Atomic; Molecular and Condensed Matter Physics; Fysik med inriktning mot atom- molekyl- och kondenserande materiens fysik;

    Sammanfattning : Theoretical studies of lattice- and spin-polarons are presented in this thesis, where the primary tool is ab-initio electronic structure calculations. The studies are performed with employment of a variety of analytical and computational methods. LÄS MER

  5. 9. Amorphous and crystalline functional materials from first principles

    Författare :Leyla Isaeva; Olle Eriksson; Jörg Neugebauer; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; first-principles theory; lattice dynamics; phase transitions; amorphous materials; tribology; ultrafast magnetism;

    Sammanfattning : This thesis deals with various functional materials from first-principles methods and is divided into two major parts according to the underlying atomic structure of the system under study. The first part of the thesis deals with the temperature-induced structural phase transitions in metallic  β'-AuZn and perovskite oxide LiOsO3. LÄS MER

  7. 10. Theoretical Description of the Electron-Lattice Interaction in Molecular and Magnetic Crystals

    Författare :Elham Mozafari; Igor A. Abrikosov; Sven Stafström; George Malcolm Stocks; Linköpings universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Molecular crystals; Charge transport; Polaron; Magnetic materials; Paramagnetic state; Molecular dynamics;

    Sammanfattning : Electron-lattice interactions are often considered not to play a major role in material's properties as they are assumed to be small, the second-order effects. However, this study shows the importance of taking these effects into account in the simulations. LÄS MER