Sökning: "Bloch equations"

Visar resultat 1 - 5 av 11 avhandlingar innehållade orden Bloch equations.

  1. 1. Spatiotemporal carrier dynamics in graphene

    Författare :Roland Jago; Chalmers tekniska högskola; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; spatiotemporal dynamics; density matrix formalism; graphene; relaxation dynamics; carrier multiplication; Bloch equations; photoconduction effect; bolometric effect;

    Sammanfattning : Graphene as an atomically thin material exhibits remarkable optical and electronic properties that suggest its technological application in novel optoelectronic devices, such as graphene-based photodetectors and lasers. To understand the properties of such devices on a microscopic level, we study the interplay of optical excitation, carrier-carrier, carrier-phonon, and carrierphoton scattering as well as diffusion processes. LÄS MER

  3. 2. Effective properties of heterogeneous materials with applications in electromagnetics

    Författare :Christian Engström; Institutionen för elektro- och informationsteknik; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; homogenization; optics; acoustics; Electromagnetism; structural parameters; anisotropic material; inverse homogenization; Bloch waves; Maxwell s equations; Elektromagnetism; optik; akustik; Inverse bounds;

    Sammanfattning : Composite materials, i.e, mixtures of two or more materials, are commonly used in industry, because they often have outstanding properties in comparison with the original materials. In many cases the inhomogeneities are on a very fine scale, which makes it difficult to perform a full numerical simulation of the material. LÄS MER

  4. 3. 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

  5. 4. Electron dynamics in graphene in the presence of an electrical field

    Författare :Roland Jago; Chalmers tekniska högskola; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Bloch equations; density matrix formalism; graphene; relaxation dynamics; photoconduction effect; carrier multiplication;

    Sammanfattning : Graphene as atomically thin two-dimensional material exhibits remarkableoptical and electronic properties that suggest its technological applicationin novel optoelectronic devices, such as graphene-based lasers and photodetectors.The linear electronic bandstructure and the vanishing band gap atthe Dirac point open up new relaxation channels, such as Auger scattering. LÄS MER

  7. 5. Microscopic Theory of Externally Tunable Exciton Signatures of Two-Dimensional Materials

    Författare :Maja Feierabend; Chalmers tekniska högskola; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; localized states; density matrix formalism; magnetic field; transition metal dichalcogenides; Bloch equations; organic inorganic heterostructures; dark excitons; strain;

    Sammanfattning : Atomically thin transition metal dichalcogenides (TMDs) are in the focus of current research due to their efficient light-matter interaction and the remarkably strong Coulomb interaction that leads to tightly bound excitons. Due to their unique band structure, TMDs show a variety of bright and optically inaccessible dark excitonic states. LÄS MER