SKM 2023 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 75: Focus Session: Ultrafast Dynamics in Nanostructures I
O 75.9: Vortrag
Donnerstag, 30. März 2023, 13:00–13:15, GER 38
Nanoscale coherent phonon excitation via plasmon-matter interaction in ultrathin ZnO films — •H. Wiedenhaupt1, S. Liu1,2, L. Parra López1, A. Hammud1, I. Hamada3, F. Schulz1,4, M. Wolf1, T. Kumagai1,2, and M. Müller1 — 1Fritz Haber Institute, Berlin, Germany — 2Institute for Molecular Science, Okazaki 444-8585, Japan — 3Hunan University, Hunan 410082, P. R. China — 4CIC NanoGUNE, San Sebastian, Spain
In crystalline nanostructures, nanoscale variations of the lattice and/or electronic structure can alter their microscopic response and its interaction with light. Using light-coupled scanning tunneling microscopy (STM) with plasmonic junctions, we demonstrated recently that the local electronic structure of ultrathin ZnO on Ag(111) can strongly affect light-matter interaction on the nanoscale. Specifically, resonant laser excitation of these films seems crucial for tip-enhanced Raman spectroscopy (TERS) [1] and for the nanoscale excitation and observation of coherent phonon dynamics [2]. CPs are excited by femtosecond excitation of localized surface plasmons (LSP), and modulate the femtosecond photocurrent in the STM on ultrafast time scales. To better understand the optical excitation mechanism in these films, we measure plasmon-enhanced STM-induced luminescence, which allows us to correlate the local electronic structure of the films with their light coupling efficiency on the nanoscale. [1] S. Liu, Nano Lett. 19, 5725 (2019), [2] S. Liu et al., Sci. Adv. 8, eabq5682 (2022)