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O: Fachverband Oberflächenphysik

O 14: Ultrafast electron dynamics at surface and interfaces I

O 14.11: Vortrag

Montag, 9. März 2026, 17:45–18:00, TRE/MATH

Temporal Advancement of Photoelectrons emitted via Evanescent Waves — •Luis Maschmann, Andreas Gebauer, Tillmann Schabbehard, and Walter Pfeiffer — Bielefeld University, Universitätsstr. 25, 33615 Bielefeld

Photoelectron emission dynamics in solids is governed both by propagating and evanescent wave components. Here we employ a one-dimensional Kronig-Penney model to investigate the role of evanescent waves on the photoelectron wave packet dynamics based on time-reversed LEED states within one-step theory and time-dependent Schrödinger equation simulations. Using a Kronig-Penney potential with a large bandgap, we can clearly distinguish the dynamics for evanescent and propagating photoelectron emission channels. For emission via evanescent states, i.e., within the final state bandgap, the photoelectron appears temporally advanced and seemingly originates from the bulk-vacuum interface, although the emitter well is located well below the interface. Our results establish a direct analogy to the temporal evolution of a wave packet undergoing quantum mechanical tunneling through a potential barrier and significantly influence the interpretation of attosecond time-resolved photoemission delays.

Keywords: Photoemission; Evanescent Waves; One-Step-Theory; Photoemission Delays