Sökning: "band structure calculations"

Visar resultat 11 - 15 av 129 avhandlingar innehållade orden band structure calculations.

  1. 11. Electronic structure and spectroscopy calculations in fuel cell catalysis

    Författare :Henrik Öberg; Lars G.M. Pettersson; Göran Lindbergh; Stockholms universitet; []
    Nyckelord :Chemical Physics; kemisk fysik;

    Sammanfattning : This thesis presents joint experimental and theoretical studies of surface phenomena at an electronic structure level in proton exchange membrane fuel cells (PEM-FC's). The fuel cell activity can be related to the oxygen reduction taking place at the cathodic surface through the oxygen reduction reaction (ORR). LÄS MER

  3. 12. First principles methods for electronic structure calculations of solids

    Författare :Martin Springer; Matematisk fysik; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; screened interaction; T-matrix; vertex function; GW approximation; Green function; density functional theory; gradient expansion; order N method; Physics; Fysik;

    Sammanfattning : A straightforward gradient expansion of the exchange energy of a perturbed electron gas is performed. Studied perturbations range from very weak to those that produce, e.g., a silicon-like band structure with a band gap. LÄS MER

  4. 13. In pursuit of next generation photovoltaics : An electronic structure study of emerging solar cell materials

    Författare :Axel Erbing; Michael Odelius; David Scanlon; Stockholms universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Solar cells; computational physics; density functional theory; electronic structure; molecular dynamics; Solceller; beräkningsfysik; täthetsfunktionalteori; elektronstruktur; molekyldynamik; Theoretical Physics; teoretisk fysik;

    Sammanfattning : The development of a new generation of photovoltaic technologies is an important task in order to increase the production of clean energy. Perovskite solar cells, with an exceptionally rapid development over the last decade, have transformed into perhaps the most promising candidate to provide a low-cost alternative to conventional cells. LÄS MER

  5. 14. The rational design of lithium insertion materials for battery applications

    Författare :Helena Berg; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Chemistry; cathode materials; lithium manganese oxide; in situ neutron diffraction; Rietveld refinement; band-structure calculations; Kemi; Chemistry; Kemi; Inorganic Chemistry; oorganisk kemi;

    Sammanfattning : The transition-metal oxide spine1 LiMn2O4 is a promising cathode material for high-capacity lithium-ion batteries. Structure-property relationships pertaining to the electrochemical cycling behaviour of LiMn2O4 have been studied. LÄS MER

  7. 15. Numerical Studies of Energy Gaps in Photonic Crystals

    Författare :Andreas Rung; Carl-Gustaf Ribbing; Norbert Kaiser; Uppsala universitet; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Materials science; photonic crystals; polaritonic; periodic structures; Reststrahlen; band structure; energy gap; Materialvetenskap; Materials science; Teknisk materialvetenskap;

    Sammanfattning : The concept of photonic crystals was born in the late 1980's when two important letters were published that showed the possibility to control light propagation by a periodic structure. A photonic crystals consists of two or more materials with different dielectric functions periodically arranged on the length scale of light. LÄS MER