RAMAN SPEKTROSKOPIE DISSERTATION

Diese Vielseitigkeit macht ihre theoretische Beschreibung jedoch sehr herausfordernd, sodass bis heute kein allgemeiner ab initio Zugang existiert. All documents in ORBi lu are protected by a user license. 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. 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.

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. Schmidt, Thomas Member of the jury: This applies not only to graphene but also to other two-dimensional materials of current interest, such as MoTe2 and MoS2. 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. 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. Dies trifft auch auf andere zweidimensionale Materialien zu, wie z. 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.

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

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.

raman spektroskopie dissertation

It can be applied also to strongly correlated systems, for which the currently used methods are not entirely satisfactory or insufficient. Diese Vielseitigkeit macht ihre theoretische Beschreibung jedoch sehr herausfordernd, sodass bis heute kein allgemeiner ab initio Zugang existiert.

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

This applies not only to graphene but also to other two-dimensional materials of current interest, such as MoTe2 and MoS2. Doctoral thesis Discipline s: ORBi lu Detailled reference. The latter has so far not been possible with state-of-the-art methods, which can only take into account one of the two effects.

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

raman spektroskopie dissertation

Our new method goes beyond the limitations spektrosokpie 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. 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.

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Dies trifft auch auf andere zweidimensionale Materialien zu, wie z.

raman spektroskopie dissertation

Lastly, we present work on the application of magneto- Raman spectroscopy as a probe for many-body effects in graphene. Docteur en Physique; Doktor der Naturwissenschaften Number of pages: Wirtz, Ludger Stampfer, Christoph President of the jury: 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 spektroakopie screened electron-phonon coupling.

Completed Theses

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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.

Schmidt, Thomas Member of the jury: Physics and Materials Science To cite this reference: 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.

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.