Search for dissertations about: "electronic excitations"

Showing result 1 - 5 of 70 swedish dissertations containing the words electronic excitations.

  1. 1. Electronic materials : growth and characterisation

    Author : Michael A. Grishin; Ulf O. Karlsson; Massimo Sancrotti; KTH; []
    Keywords : ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Electrophysics; Photoemission; Ultra-short laser pulse; Thin film; Laser deposition; InSb; InAs; GaSb; Ferroelectrics; Elektrofysik; Electrophysics; Elektrofysik;

    Abstract : In this thesis the InSb(111), InAs(111) and GaSb(001) surfaces have been studied by means of time- and angle-resolved photoemission spectroscopy based upon the femtosecond laser system. The pump-and-probe technique allows to analyse both electron states in the valence band and normally unpopulated electron states above the valence band, which can be occupied by transiently excited carriers at the optically pumped surface. READ MORE

  2. 2. Theoretical studies of collective electronic excitations in low-dimensional structures

    Author : Zhe Yuan; Chalmers University of Technology; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; linear atomic chains; hydrogen storage; nanodisks; dielectric response; surface plasmon resonances; electron gas model; electronic excitation; metallic thin films; time-dependent density functional theory;

    Abstract : During the past decade, nanoplasmonics and nanophotonicshas emerged as a new branch of nanosciences with many novelapplications. Central in this development is the localized surface plasmon resonance (LSPR) tunable by the sizes and shapes at nanometer scale. READ MORE

  3. 3. Lateral Superlattices in Commensurate Magnetic Fields: Electronic Structure, Transport and Optical Properties

    Author : Egidijus Anisimovas; Matematisk fysik; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; tunneling; Physics; collective excitations; optical absorption; quantum Hall effect; electronic structure; two-dimensional electron systems; lateral superlattices; Electromagnetism; Fysik; optics; acoustics; Elektromagnetism; optik; akustik; Fysicumarkivet A:2001:Anisimovas;

    Abstract : The present thesis is devoted to the theoretical study of two-dimensional electron systems moving in a modulated lateral periodic potential and a competing perpendicular magnetic field. The three introductory chapters offer a brief exposition of the basic issues in this area -- the description of the electron motion in a prependicular magnetic field, the group of magnetic translations and the commensurability phenomena -- at an elementary level. READ MORE

  4. 4. Photoemission from Alkali Metal Overlayers: Quantum Wells, Photoelectron Interference and Atomic Structure Changes

    Author : Dan Claesson; Chalmers University of Technology; []
    Keywords : quantum well states; surface structure; alkali metals; angle resolved photoemission; surface electronic phenomena; thin films; collective excitations; electronic structure;

    Abstract : Angle resolved photoelectron spectroscopy is used to investigate alkali metal overlayers on noble metal surfaces. The work deals with interference in photoemission, bulk electronic structure and adsorption induced changes of atomic structure, respectively. The relative importance of surface and bulk in photoemission has remained largely unexplored. READ MORE

  5. 5. The Electronic Structure of Organic Molecular Materials : Theoretical and Spectroscopic Investigations

    Author : Iulia Emilia Brumboiu; Barbara Brena; Biplab Sanyal; Olle Eriksson; Jakob Schiøtz; Uppsala universitet; []
    Keywords : NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURVETENSKAP; NATURVETENSKAP; NATURAL SCIENCES; NATURAL SCIENCES; materials theory; electronic structure; photoelectron spectroscopy; near-edge X-ray absorption fine structure; Physics with spec. in Atomic; Molecular and Condensed Matter Physics; Fysik med inriktning mot atom- molekyl- och kondenserande materiens fysik; Materialvetenskap; Materials Science;

    Abstract : In the present thesis the electronic properties of two organic molecules were studied by means of density functional theory (DFT) in connection to their possible applications in organic photovoltaics and molecular spintronics respectively.The first analysed system is the C60 derivative PCBM extensively used in polymer solar cells for the charge separation process. READ MORE