Sökning: "electron-phonon interaction"

Visar resultat 6 - 10 av 17 avhandlingar innehållade orden electron-phonon interaction.

  1. 6. Microscopic Mechanisms of the Formation, Relaxation and Recombination of Excitons in Two-Dimensional Semiconductors

    Författare :Samuel Brem; Chalmers tekniska högskola; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; relaxation dynamics; 2D materials; density matrix formalism; excitons; exciton-phonon interaction; Bloch equations;

    Sammanfattning : Monolayers of Transition Metal Dichalcogenides (TMDs) present a giant leap forward towards the realization of semiconductor devices with atomic scale thickness. As a natural consequence of their two-dimensional character TMDs exhibit a reduced dielectric screening, leading to the formation of unusually stable excitons, i.e. LÄS MER

  3. 7. First principles study of oxide semiconductors for solar energy applications

    Författare :Maofeng Dou; Clas Persson; Huda Muhammad N.; Sergey Simak; Anna Delin; Peter Johansson; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; photocatalysis; water splitting; oxynitrides; dielectric function; first-principles calculation; density functional theory; electronic structures; Casimir interaction; Teknisk materialvetenskap; Materials Science and Engineering;

    Sammanfattning : The objectives of this thesis are to understand the electronic structures of oxides and oxynitrides for photocatalytic water splitting, examine the Casimir interaction between oxides, and explore possible approach to bridge the Casimir force and material properties for advanced material research. The studies were performed in the framework of the density functional theory, many-body perturbation theory, i. LÄS MER

  4. 8. Superconducting THz mixers based on MgB2 film

    Författare :Stella Bevilacqua; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; bolometers; IF bandwidth.; superconductors; MgB2; THz Detectors; mixers;

    Sammanfattning : Superconducting NbN hot electron bolometer (HEB) mixers are widely used in terahertz radio astronomy. Such mixers have superior performance compared to SIS and Schottky diode mixers at frequency above 1THz. However, their drawback is a limited IF bandwidth. LÄS MER

  5. 9. Non-equilibrium fermions within lattice density functional theory: quantum transport and ultracold-atom phenomena

    Författare :Alexey Kartsev; Matematisk fysik; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Fysicumarkivet A:2013:Kartsev;

    Sammanfattning : Cutting-edge technology needs small, ultrafast devices, operational in a wide range of regimes. This calls for solids with novel, unconventional and tailorable properties. Great progress is expected from materials in which electron-electron and electron-phonon correlations strongly affect the dynamics ( i.e. LÄS MER

  7. 10. Study of MgB2 and YBa2Cu3O7-x Microbolometers for THz Sensing Applications

    Författare :Stella Bevilacqua; Chalmers tekniska högskola; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; THz Detectors; bolometers; IF bandwidth; YBa2< sub>Cu3< sub>O7-x< sub>; Terahertz frequency; HEB; MgB2< sub>; noise; superconductors;

    Sammanfattning : In this thesis, two novel THz detectors based on magnesium diboride (MgB2)and yttrium barium copper oxide (YBa2Cu3O7-x) are presented. In particular,MgB2 superconductor is used for the investigation of hot-electron bolometer(HEB) mixers, while YBa2Cu3O7-x is explored in microbolometers for room-temperaturecoherent and incoherent detection. LÄS MER