Sökning: "lattice dynamics"

Visar resultat 1 - 5 av 128 avhandlingar innehållade orden lattice dynamics.

  1. 1. Lattice dynamics : From fundamental research to practical applications

    Författare :Johan Tidholm; Igor A. Abrikosov; Olle Hellman; Ferenc Tasnadi; Gerd Steinle-Neumann; Linköpings universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES;

    Sammanfattning : The reason to perform calculations in material science usually falls into one of two categories: to predict or explain the origin of material properties. This thesis covers first-principle calculations for solids at extreme conditions, from both of the two mentioned categories. LÄS MER

  3. 2. Ab initio Lattice Dynamics : Hydrogen-dense and Other Materials

    Författare :Duck Young Kim; Rajeev Ahuja; Richard Needs; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Density functional theory; Density functional perturbation theory; Hydrogen-dense materials; Phase transition; High pressure; Ab initio lattice dynamics; Superconductivity; Quasi-particle approximation; Physics; Fysik;

    Sammanfattning : This thesis presents a theoretical study of materials under high pressure using ab initio lattice dynamics based on density functional theory and density functional perturbation theory using both super-cell and linear response approach. Ab initio lattice dynamics using super-cell approach is applied to compare our theoretical predictions with experimental findings. LÄS MER

  4. 3. Dynamics in Ceria and Related Materials from Molecular Dynamics and Lattice Dynamics

    Författare :Anders Gotte; Kersti Hermansson; Micael Baudin; Anatoly Belonoshko; Uppsala universitet; []
    Nyckelord :Inorganic chemistry; molecular dynamics; diffusion; surface dynamics; ionic surfaces; Oorganisk kemi;

    Sammanfattning : In discussions of heterogeneous catalysis and other surface-related phenomena, the dynamical properties of the catalytic material are often neglected, even at elevated temperatures. An example is the three-way catalyst (TWC), used for treatment of exhaust gases from combustion engines operating at several hundred degrees Celsius. LÄS MER

  5. 4. Electron-Lattice Dynamics in pi-Conjugated Systems

    Författare :Magnus Hultell (Andersson); Sven Stafström; Alexander Onipko; Linköpings universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Polaron dynamics; Exciton dynamics; pi-conjugated systems; Su-Schrieffer-Heeger SSH model; Adiabaticity; Charge carrier transport; Organic electronics.; Computational physics; Beräkningsfysik;

    Sammanfattning : In this thesis we explore in particular the dynamics of a special type of quasi-particle in pi-conjugated materials termed polaron, the origin of which is intimately related to the strong interactions between the electronic and the vibrational degrees of freedom within these systems. In order to conduct such studies with the particular focus of each appended paper, we simultaneously solve the time-dependent Schrödinger equation and the lattice equation of motion with a three-dimensional extension of the famous Su-Schrieffer-Heeger (SSH) model Hamiltonian. LÄS MER

  7. 5. Electronic Structure and Lattice Dynamics of Elements and Compounds

    Författare :Petros Souvatzis; Olle Eriksson; Anna Delin; Dario Alfé; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Atomic and molecular physics; electronic structure; lattice dynamics; first-principles theory; self-consistent lattice dynamical calculation; elasticity; super plasticity; electronic topological transition; equation of state; Atom- och molekylfysik;

    Sammanfattning : The elastic constants of Mg(1-x)AlxB2 have been calculated in the regime 0.... LÄS MER