Regensburg 2025 – scientific programme
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O: Fachverband Oberflächenphysik
O 43: Scanning Probe Microscopy: Light-Matter Interactions at the Atomic Scale II
O 43.7: Talk
Tuesday, March 18, 2025, 15:30–15:45, H24
Attosecond charge transfer in atomic-resolution scanning tunnelling microscopy — •Katharina Glöckl1, Simon Maier1, Raffael Spachtholz1, Carlos Bustamante2, Korbinian Pürckhauer1, Franz J. Giessibl1, Franco Bonafé2, Markus A. Huber1, Angel Rubio2, Jascha Repp1, and Rupert Huber1 — 1Department of Physics & Regensburg Center for Ultrafast Nanoscopy (RUN), Universität Regensburg — 2Max Planck Institute for the Structure and Dynamics of Matter, Hamburg
Scanning tunnelling microscopy (STM) driven with single-cycle terahertz pulses has afforded atomic-scale slow motion videos of single molecular orbitals. Driving tunnel currents with the carrier field of near-infrared light could improve the temporal resolution from ~100 fs down to attoseconds. Yet, competing multi-photon processes and thermal effects pose severe challenges in this spectral domain.
Here, we introduce an attosecond STM concept that is largely immune against thermal artifacts. By pulse synthesis, we periodically vary the waveform of single-cycle near-infrared pulses to drive tunnelling currents while keeping the thermal load on the tip constant. In a non-degenerate pump-probe scheme, we observe clear attosecond features in the sub-cycle currents and demonstrate atomic resolution by taking snapshot images of a single Cu adatom on a silver surface. Our results pave the way to recording the fastest relevant dynamics of electrons within atoms, molecules and quantum materials in actual attosecond atomic videography.
Keywords: Lightwave driven scanning tunneling micoscopy; Attosecond charge transfer; Ultrafast electron dynamics; Atomic scale resolution; Carrier envelope phase control