Sökning: "polarons"

Visar resultat 1 - 5 av 11 avhandlingar innehållade ordet polarons.

  1. 1. On the defective origin of conductive and structural properties of oxides: insights from first principles

    Författare :Anders Lindman; Chalmers University of Technology; []
    Nyckelord :NATURVETENSKAP; NATURVETENSKAP; NATURAL SCIENCES; NATURAL SCIENCES; point defects; thermodynamic modeling; proton conductors; oxyhydrides; density-functional theory; BaZrO3; polarons; grain boundaries; space charges; oxides;

    Sammanfattning : Oxides are versatile materials with applications in many different research fields; especially those related to clean energy technologies, such as fuel cells, batteries and solar panels. Many functional properties of these materials derive from lattice imperfections, or defects, and a lot of effort has been put into fine tuning these materials by modifying their structure on the atomic scale. LÄS MER

  2. 2. Theoretical studies of lattice- and spin-polarons

    Författare :Nina Bondarenko; Olle Eriksson; Natalia Skorodumova; Manuel Pereiro; Maria Roser Valenti Vall; Uppsala universitet; []
    Nyckelord :NATURAL SCIENCES; NATURVETENSKAP; 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

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

    Författare :Erik Jedvik Granhed; Chalmers University of Technology; []
    Nyckelord :NATURVETENSKAP; NATURVETENSKAP; NATURAL SCIENCES; 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

  4. 4. Electronic and optical properties of conducting polymers from quantum mechanical computations

    Författare :Amina Mirsakiyeva; Anna Delin; Igor Zozoulenko; KTH; []
    Nyckelord :NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURVETENSKAP; NATURVETENSKAP; NATURAL SCIENCES; NATURAL SCIENCES; density functional theory; DFT; Car-Parrinello molecular dynamics; CPMD; tigh-binding; poly 3; 4-ethylenedioxythiophene ; PEDOT; selenium; PEDOS; tellurium; PEDOTe; poly p-phenylene ; poly para-phenylene ; poly 1; 4-phenylene ; naphthobischalcogenadiazoles; Physics; Fysik;

    Sammanfattning :     Conductive polymers are also known as "organic metals" due to their semiconducting properties. They are found in a wide range of applications in the field of organic electronics. However, the growing number of experimental works is not widely supported with theoretical calculations. LÄS MER

  5. 5. Energy Storage Materials: Insights From ab Initio Theory : Diffusion, Structure, Thermodynamics and Design

    Författare :Rafael Barros Neves de Araújo; Rajeev Ahuja; Graeme Henkelman; Uppsala universitet; []
    Nyckelord :Density Functional Theory; Defects Diffusion; Thermodynamics and Batteries.;

    Sammanfattning : The development of science and technology have provided a lifestyle completely dependent on energy consumption. Devices such as computers and mobile phones are good examples of how our daily life depends on electric energy. LÄS MER