Regensburg 2025 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 7: Focus Session Ultrafast Electron Microscopy at the Space-Time Limit I

O 7.3: Vortrag

Montag, 17. März 2025, 11:00–11:15, H11

Mechanisms and Dynamics of Electron Emission from Graphitic Surfaces: Insights from Correlated and Time-Resolved Spectroscopies — •Alessandra Bellissimo¹, Florian Simperl¹, Felix Blödorn¹, Wolfgang S.M. Werner¹, Gyula Halasi², László Óvári², Csaba Vass², Nikolett Oláh², Zoltán Filus², Tímea Grósz², Chinmoy Biswas², Balázs Major², Imre Seres², Aref Imani¹, Paolo A. Carpeggiani¹, Maosheng Hao¹, and Florian Libisch¹ — ¹TU WIEN, Vienna, Austria — ²ELI-ALPS, Szeged, Hungary

The electron emission behaviour of graphitic surfaces was investigated using advanced spectroscopic methods alongside static & time-resolved Photo-Electron Emission Microscopy (PEEM). At TU WIEN, electron-pair coincidence spectroscopy on pyrolytic graphite detected correlated electron pairs from single scattering events, directly linking energy-loss processes to the secondary electron (SE) spectrum. The (π+σ)-plasmon was resolved in terms of the involved interband transitions revealing strong final-state resonances in the SE spectrum. Static photoemission from graphite(0001) was studied using PEEM at the NanoESCA end station at ELI-ALPS, employing extreme ultraviolet linearly polarised photons generated via High-Harmonic Generation in Argon. The k-space-resolved photoelectron (PE) signal associated to the above-mentioned final-state resonances in the SE-spectrum reflects the symmetry of the conduction bands involved in the PE-emission process. Attosecond time- and k-space-resolved RABBITT measurements provided insights into PE-emission dynamics across the Brillouin zone.

Keywords: secondary & photoelectron emission; time-resolved spectroscopy; electron-pair spectroscopy; graphite; electron momentum microscopy