RAMAN SPEKTROSKOPIE DISSERTATION

In addition to the development of a consistent and comprehensive description of Raman scattering, we derive a novel approach for the calculation of phonon frequencies and the screened electron-phonon coupling. Docteur en Physique; Doktor der Naturwissenschaften Number of pages: As a first test case, we apply our theory to graphene, for which we use it to study the laser frequency and Fermi energy dependence of the Raman G-peak intensity. This applies not only to graphene but also to other two-dimensional materials of current interest, such as MoTe2 and MoS2. Here we focus on the description of the phenomenon of magneto-phonon resonances and how it can be used to probe electronic excitation energies and to extract electron and phonon lifetimes. Besides these theoretical developments, we present concrete computational recipes for the calculation of Raman intensities that allow the inclusion of both excitonic effects and non-adiabatic effects of lattice vibrations. Lastly, we present work on the application of magneto- Raman spectroscopy as a probe for many-body effects in graphene.

Dies trifft auch auf andere zweidimensionale Materialien zu, wie z. Lastly, we present work on the application of magneto- Raman spectroscopy as a probe for many-body effects in graphene. As a first test case, we apply our theory to graphene, for which we use it to study the laser frequency and Fermi energy dependence of the Raman G-peak intensity. Besides these theoretical developments, we present concrete computational recipes for the calculation of Raman intensities that allow the inclusion of both excitonic effects and non-adiabatic effects of lattice vibrations. Our new method goes beyond the limitations of the methods currently in use and will permit the computation of phonon-related quantities also in systems with strong correlation effects such as Kohn anomalies e. ORBi lu Detailled reference.

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In addition to the development of a consistent and comprehensive description of Raman scattering, we derive a novel approach for the calculation of phonon frequencies and the screened electron-phonon coupling. This applies not only to graphene but also to other two-dimensional materials of current interest, such as MoTe2 and MoS2.

raman spektroskopie dissertation

Diese Vielseitigkeit macht ihre theoretische Beschreibung jedoch sehr herausfordernd, sodass bis heute kein allgemeiner ab initio Zugang existiert. Doctoral thesis Discipline s: Schmidt, Thomas Member of the jury: The latter has so far not been possible with state-of-the-art spektrodkopie, which can only take into account one of the two effects.

Completed Theses | 5th Institute of Physics | University of Stuttgart

Lastly, we present work on the application of magneto- Raman spectroscopy as a probe for many-body effects in graphene. In this thesis, we aim to fill this gap and present a coherent theory of Raman scattering within the framework of many-body perturbation theory. As a first test case, we apply our theory to graphene, for which we use it to study the laser frequency and Fermi energy dependence of the Raman G-peak intensity.

We develop a novel and general, correlation function-based approach for the calculation of Raman scattering rates that can potentially also be applied to ultra-fast Raman spectroscopy out of equilibrium.

Our new method goes beyond the limitations of the methods currently in use and will permit the computation of phonon-related quantities also in systems with strong correlation effects such as Kohn anomalies e. It can be applied also to strongly correlated systems, for which the currently used methods are not entirely satisfactory or insufficient.

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Physics and Materials Science To cite this reference: University of Luxembourg Library. Dies trifft auch auf andere zweidimensionale Materialien zu, wie z.

Completed Theses

All documents in ORBi lu are protected by a user license. This versatility, however, makes its theoretical description very challenging and, up to now, no fully satisfactory and general way for the calculation of Raman spectra from first principles exists. Docteur en Physique; Doktor der Naturwissenschaften Number of pages: ORBi lu Detailled reference.

Besides these theoretical developments, we present concrete computational recipes for the calculation of Raman intensities that allow the inclusion of both excitonic effects and non-adiabatic effects of lattice vibrations.

O pen R epository and Bi bliography.

raman spektroskopie dissertation

Wirtz, Ludger Stampfer, Christoph President of the jury: The flexibility of our approach also allows us to demonstrate that non-resonant processes and quantum mechanical interference effects play a significant role in Raman scattering.

Here we focus on the description of the phenomenon of magneto-phonon resonances and how it can be used to probe electronic excitation energies and to extract electron and phonon lifetimes.