Regensburg 2025 – scientific programme
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O: Fachverband Oberflächenphysik
O 10: Focus Session Ultrafast Electron Microscopy at the Space-Time Limit II
O 10.5: Invited Talk
Monday, March 17, 2025, 16:15–16:45, H2
Ultrafast exciton dynamics in momentum space — Alexander Neef1, Tommaso Pincelli1,2, Lawson Lloyd1, Shuo Dong1, Samuel Beaulieu1, Tania Mukherjee1,2, Sebastian Hammer3, Malte Selig2, Dominik Christiansen2, Andreas Knorr2, Martin Wolf1, Jens Pflaum3, Laurenz Rettig1, and •Ralph Ernstorfer1,2 — 1Fritz-Haber-Institut der Max-Planck-Gesellschaft, 14195 Berlin, Germany — 2Technische Universität Berlin, 10623 Berlin, Germany — 3Julius-Maximilian-Universität Würzburg, 97070 Würzburg, Germany
Time- and angle-resolved photoemission spectroscopy (trARPES) provides a quantum-state-resolved picture of the ultrafast dynamics of many-body states like excitons in non-equilibrium states of matter. Following the formation and scattering of excitons in momentum space in real time reveals all key properties of the excitons like binding energy, exciton-phonon coupling, and the real-space distribution of the many-body wave functions. Additionally, information about the orbital properties and Berry curvature is encoded in the multidimensional trARPES signals. Applied to heterostructures, the ultrafast exciton and charge dynamics across interfaces reveal the mechanism of charge and energy transfer processes. We will exemplify this approach for transition metal dichalcogenides heterostructures, molecular crystals, and layered semiconducting antiferromagnets.
References: S. Dong et al., Nature Commu. 14, 5057 (2023); T. Pincelli et al., Adv. Mater. 2209100 (2023), A. Neef et al., Nature 616, 275 (2023), S. Beaulieu et al., Sci. Adv. 10, eadk3897 (2024).
Keywords: ultrafast dynamics; low-dimensional materials; trARPES; exciton dynamics