Browsing Fakultät für Physik (inkl. GAUSS) by Referee "Mathias, Stefan Prof. Dr."
Now showing items 1-20 of 20
-
Radio-frequency controlled low-energy electron pulses
(2024-08-23)Electron beams are invaluable for probing material structures and dynamic processes due to their large scattering cross sections and the versatility of tunable electron optics for diffraction and microscopy. Pulsed electron ... -
Ultrafast momentum microscopy of dark exciton dynamics in real- and reciprocal-space
(2023-12-22)Combining both worlds of momentum and real-space time-resolved momentum microscopy, this thesis introduces a new approach to probe the entire exciton landscape and dynamics of twisted TMD heterostructures with momentum-, ... -
Unraveling Femtosecond Spin and Charge Dynamics with EUV T-MOKE Spectroscopy
(2023-12-15)In this thesis, a novel transverse magneto-optical Kerr effect (T-MOKE) setup with extreme ultraviolet light from high-harmonic generation between 30 and 72 eV is used to study the spectrally-resolved spin and charge ... -
Non-equilibrium Phases in Jahn-Teller-distorted Perovskite Manganites
(2023-12-04)Optical control of condensed matter, being inherently fast and energy efficient, sparks hope for potential technical applications. However, these require a fundamental understanding of the physical mechanisms behind. In ... -
Ultrafast spin dynamics in FeNi alloys
(2023-11-17)In this thesis, the optical intersite spin transfer in ferromagnetic FeNi alloys is studied on the femtosecond timescale. Extreme ultraviolet transverse magneto-optical Kerr effect spectroscopy (EUV T-MOKE) is used to ... -
Symmetries and correlations in solids probed by ultrafast high-harmonic spectroscopy
(2023-11-13)Novel material systems with correlated and tunable properties promise to push the boundaries of current information processing and energy management technologies. Their investigation requires simultaneous access to multiple ... -
Phase-Dependent Energy Dissipation Processes in La0.7Sr0.3MnO3 and (La0.6Pr0.4)0.7Ca0.3MnO3 after an Ultrashort Optical Excitation
(2023-08-31)La0.7Sr0.3MnO3 (LSMO) and (La0.6Pr0.4)0.7Ca0.3MnO3 (LPCMO) are perovsikte manganites which both show a ferromagnetic-to-paramagnetic phase transition. Interestingly, the development of the new phase when crossing the ... -
Imaging vortex pinning and gyration by time-resolved and in-situ Lorentz microscopy
(2023-03-08)Magnetism encompasses a large variety of scientifically interesting and industrially valuable phenomena. In particular, nanoscopic magnetic textures—such as vortices, merons and skyrmions—have been in the spotlight of ... -
Far-from-Equilibrium Quasiparticle Dynamics in Graphene
(2023-01-17)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 ... -
Local excitation of confined molecule-surface hybrid systems
(2022-11-28)Molecule-surface hybrid systems promise solutions for a variety of technological challenges – including the development of efficient catalysts as well as of molecular electronic devices. In this work, different molecule ... -
Combined Study of Local Spectroscopy and Macroscopic Electronic Transport of the Correlated Honeycomb Spin-Orbit Mott Insulator Na2IrO3
(2022-04-11)The search for novel phenomena that exceeds and interconnects our existing knowledge is at the heart of every scientific effort. Physics, and particularly solid-state research, is no exception. If anything, the ... -
Ultrafast Probing and Coherent Vibrational Control of a Surface Structural Phase Transition
(2021-08-26)The present thesis explores the coherent control of surface structural phase transitions by all-optical manipulation of key vibrational modes. To this end, ultrafast low-energy electron diffraction (ULEED) in combination ... -
Ultrafast electron dynamics measured with a novel time-resolved high-repetition rate momentum microscopy setup
(2021-03-25)In this thesis, a new generation of a trARPES experiment has been successfully built up from scratch combining the advantages of a ToF momentum microscope with a lab-based HHG source, delivering femtosecond EUV pulses, ... -
Scanning Tunneling Spectroscopy of Rare Earth Hexaborides
(2020-12-22)Rare earth hexaborides are a well-suited model system for the exploration of correlation physics. The varying 4f occupation of the rare earth elements result in a richness of correlated electron phenomena, which harbor ... -
Non-equilibrium structural Dynamics of incommensurate Charge-Density Waves
(2020-07-01)In recent years, charge-density wave (CDW) systems have been studied extensively, as they provide a diverse testing field for basic concepts in electron-phonon coupling, electron correlation, and structural phase transitions. ... -
Ultrafast Lorentz Microscopy using High-Coherence Electron Pulses
(2019-05-08)Information processing and storage applications demand increasing miniaturization and operation speeds, where optical manipulation of magnetic order may play a very important role. It is hence essential to study how light ... -
Ultrafast low-energy electron diffraction at surfaces
(2019-02-22)Due to their reduced dimensionality, surfaces and quasi two-dimensional materials exhibit numerous intriguing physical phenomena that drastically differ from the bulk. To resolve these effects and the associated dynamics ... -
THz streaking at metal nanotips
(2018-03-20)This thesis addresses various aspects of terahertz (THz) streaking at metallic nanotips. In THz near-field streaking, electron pulses emitted by femtosecond near-infrared (NIR) pulses are accelerated in a THz-induced ... -
Coherent Control and Reconstruction of Free-Electron Quantum States in Ultrafast Electron Microscopy
(2018-01-04)The present (cumulative) thesis examines the quantum coherent interaction of ultrashort free-electron pulses with tailored optical near-fields. Multiple fields are utilised to prepare, coherently manipulate and characterise ... -
Thermalization in one-dimensional quantum-many-body systems
(2017-01-16)We consider the thermalization of the momentum distribution in two one-dimensional models. The first one is the integrable Hubbard model with an additional integrability breaking term in the Hamiltonian, which is a ...