| dc.contributor.advisor | Mathias, Stefan Prof. Dr. | |
| dc.contributor.author | Düvel, Marten | |
| dc.date.accessioned | 2023-01-17T15:05:40Z | |
| dc.date.available | 2023-01-25T00:50:08Z | |
| dc.date.issued | 2023-01-17 | |
| dc.identifier.uri | http://resolver.sub.uni-goettingen.de/purl?ediss-11858/14459 | |
| dc.identifier.uri | http://dx.doi.org/10.53846/goediss-9664 | |
| dc.format.extent | 168 Seiten | de |
| dc.language.iso | eng | de |
| dc.rights.uri | http://creativecommons.org/licenses/by/4.0/ | |
| dc.subject.ddc | 530 | de |
| dc.title | Far-from-Equilibrium Quasiparticle Dynamics in Graphene | de |
| dc.type | doctoralThesis | de |
| dc.contributor.referee | Mathias, Stefan Prof. Dr. | |
| dc.date.examination | 2022-11-25 | de |
| dc.subject.gok | Physik (PPN621336750) | de |
| dc.description.abstracteng | Comprehending far-from-equilibrium many-body interactions is one of the major goals of current ultrafast condensed matter physics research. Here, a particularly interesting but barely understood situation occurs during a strong optical excitation, where the electron and phonon systems can be significantly perturbed and the quasiparticle distributions cannot be described with equilibrium functions. In this thesis, we use time- and angle-resolved photoelectron spectroscopy (trARPES) to study such far-from-equilibrium many-body interactions for the prototypical material graphene by evaluating the low-energy non-equilibrium quasiparticle self-energy at the femtosecond timescale. The low-energy quasiparticle response, however, is at first inaccessible due to resolution artifacts caused by the spectrally our broad XUV probe pulses, which are unavoidable due to the time-bandwidth-product. Therefore, we apply a Lucy-Richardson deconvolution algorithm (LRD) to the ARPES spectra. Furthermore, we introduce rigorous benchmarking of the LRD to assure physical-meaningful results.
To deliver angle-resolved photoemission spectroscopy (ARPES) data in the necessary quality for this LRD approach, we built a trARPES setup with an extreme ultraviolet (XUV) probe source in this thesis. This XUV probe source can be switched between an energy-resolution optimized beamline and time-resolution optimized beamline.
With this experiment, we find remarkable transient renormalizations of the quasiparticle self-energy caused by the photo-induced non-equilibrium conditions, which are in accordance with first-principles theoretical modeling. These observations can be understood by ultrafast scatterings between far-from-equilibrium electrons and strongly-coupled optical phonons, which signifies the crucial role of ultrafast non-equilibrium dynamics on many-body interactions. Our results advance the understanding of many-body physics in extreme conditions, which is important for any endeavor to optically manipulate or create emergent states of matter. | de |
| dc.contributor.coReferee | Wenderoth, Martin Prof. Dr. | |
| dc.subject.eng | graphene, trARPES, nonequilibrium electron−phonon interaction, quasiparticle self-energy, Lucy−Richardson deconvolution algorithm, density functional theory | de |
| dc.identifier.urn | urn:nbn:de:gbv:7-ediss-14459-0 | |
| dc.affiliation.institute | Fakultät für Physik | de |
| dc.description.embargoed | 2023-01-25 | de |
| dc.identifier.ppn | 1831312018 | |
| dc.notes.confirmationsent | Confirmation sent 2023-01-17T15:15:01 | de |