Bereiche | Tage | Auswahl | Suche | Aktualisierungen | Downloads | Hilfe
O: Fachverband Oberflächenphysik
O 43: Scanning probe microscopy: light matter interaction at atomic scales – Poster
O 43.12: Poster
Dienstag, 10. März 2026, 14:00–16:00, P2
strong-field theory model for ultrafast electron transport in laser-assisted STM — •boyang ma1, melanie mueller1, and michael krueger2 — 1Department of Physical Chemistry, Fritz Haber Institute, 14195 Berlin, Germany — 2Department of Physics, Technion, Israel Institute of Technology, 32000 Haifa, Israel
In ultrafast scanning tunneling microscopy (USTM), the classification of light-driven currents is usually based on the well-known Keldysh parameter. Similar to the description of strong-field photoemission, it is often used to distinguish photon-driven (weak-field) and field-driven (strong-field) tunneling regimes. Here, we discuss the limitations of the Keldysh parameter in classifying light-induced electron transport in nanoscale gaps, and present a theoretical study of laser-induced electron transport in STM [1,2]. In contrast to strong-field effects in spatially extended systems, we show that the Keldysh parameter alone is insufficient to capture the electron transmission dynamics in a confined nanogap. Instead, it must be complemented by an additional parameter, ζ, defined by the laser field strength, frequency, and junction width [2]. Notably, in the THz-STM, ζ alone becomes the decisive parameter, superseding the role of the Keldysh parameter. This reflects the fact that the Keldysh parameter accounts solely for properties of the driving field and neglects geometric confinement of the tunneling junction.
[1] B. Ma and M. Krüger, Phys. Rev. Lett. 133, 236901 (2024)
[2] B. Ma and M. Krüger, Phys. Rev. A 112, 033104 (2025)
Keywords: strong-field theory; light-electron interaction; attosecond dynamics; nanostructure tunneling; light-assisted STM