Sökning: "Polaron"

Visar resultat 1 - 5 av 30 avhandlingar innehållade ordet Polaron.

  1. 1. 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

  3. 2. A Theoretical Study of Charge Transport in Molecular Crystals

    Författare :Elham Mozafari; Sven Stafström; Magnus Johansson; Linköpings universitet; []
    Nyckelord :Molecular Crystals; Charge transport; Polaron; Holstein model; Peierls coupling;

    Sammanfattning : The main objective of this thesis is to provide a deeper understanding of the charge transport phenomena occuring in molecular crystals. The focus is on the stability and the dynamics of the polaron as the charge carrier.To achieve this goal, a series of numerical calculations are performed using the semi-emprical "Holstien-Peierls" model. LÄS MER

  4. 3. 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

  5. 4. Electron-lattice dynamics in π-conjugated systems

    Författare :Magnus Hultell (Andersson); Sven Stafström; Alessandro Troisi; Linköpings universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; charge transport; electron-lattice dynamics; polaron; adiabatic transport; electron localization; internal conversion; Computational physics; Beräkningsfysik;

    Sammanfattning : The work presented in this thesis concerns the dynamics in π-conjugated hydrocarbon systems. Due to the molecular bonding structure of these systems there exists a coupling between the electronic system and the phonons of the lattice. LÄS MER

  7. 5. Image dipoles and polarons in organic semiconductors

    Författare :Yongzhen Chen; Mats Fahlman; Xianjie Liu; Yiqiang Zhan; Linköpings universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Organic electronics; Interface dipole; Polaron; Conjugated polymer; Photoelectron spectroscopy; N-type doping; Electron transport material;

    Sammanfattning : The rapid development of organic electronics depends on the synthesis of new π-conjugated molecules/polymers and the exploration of fundamental physics. However, most of the efforts have been concentrated on the former, leading to a lack of thorough understanding of many important concepts, which will become the ultimate limiting factor for overall performance and applications. LÄS MER