Dresden 2026 – wissenschaftliches Programm

Bereiche | Tage | Auswahl | Suche | Aktualisierungen | Downloads | Hilfe

O: Fachverband Oberflächenphysik

O 38: Ultrafast electron dynamics at surface and interfaces II

O 38.5: Vortrag

Dienstag, 10. März 2026, 11:30–11:45, TRE/MATH

Large relative delays for photoemission final states less than 1 eV apart — •Tillmann Schabbehard, Andreas Gebauer, Walter Enns, Luis Maschmann, and Walter Pfeiffer — Universität Bielefeld, Universitätsstr. 25, 33615 Bielefeld

The reconstruction of attosecond beating by interference of two-photon transitions (RABBITT) allows probing photoemission dynamics in atoms, molecules and solids. However, the interpretation of retrieved relative delays between different emission channels in particular for emission from solids is controversial. Here we employ spin-orbit delays in GaSe by RABBITT, i.e., relative delays for emission from the different initial states of the spin-orbit doublet, to investigate the relative photoelectron kinetics in emission channels, which differ less than 1 eV in their final state energy (E_final). Despite the small spin-orbit splitting for both Ga3d and Se3d the extraction of relative delays for the two spin-orbit doublets yields 180±53 as and 94±45 as. These unexpectedly large delays can neither be attributed to intraatomic delay mechanisms nor to kinetic propagation effects in the final state continuum. This challenges common concepts about photoelectron emission dynamics, which predict much smaller delays for E_final differences below 1 eV. Notably, the Se3d spin-orbit delay in GaSe agrees well with those observed in Bi₂Se₃ and WSe₂ indicating a general high variability of emission dynamics as function of the E_final. Predictions based on the one step model, which take into account transport via propagating and evanescent states match observations much better, while modelling based on propagation effects in the final state alone fail.

Keywords: Photoemission; Attosecond Spectroscopy; Spin Orbit Delay