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O: Fachverband Oberflächenphysik

O 23: Poster Ultrafast Electron Dynamics

O 23.7: Poster

Montag, 17. März 2025, 18:00–20:00, P2

Photo-induced electron pressure drives THz phonon in Platinum-Copper superlattice — •Jan-Etienne Pudell¹, Marc Herzog², Max Mattern², Alexander von Reppert², Daniel Schick³, Ulrike Boesenberg¹, Angel Rodriguez-Fernandez¹, Wonhyuk Jo¹, Roman Shayduk¹, Wei Lu¹, Felix Brause¹, Michel Hehn⁵, Matias Bargheer^2,4, and Anders Madsen¹ — ¹European XFEL, Germany — ²Institut für Physik, Uni Potsdam, Germany — ³MBI, Berlin — ⁴HZB Berlin, Germany — ⁵IJL, Université Lorraine, France

Using ultrafast X-ray diffraction (UXRD) at the MID end-station at the European XFEL, we investigate the ultrafast lattice dynamics of metal-metal superlattice (SL) with few atomic layers of Pt and Cu upon femtosecond photoexcitation. Our results reveal that the absorbed optical energy is rapidly localizes within the Pt layers, driving the excitation of a coherent artificial THz phonon mode defined by the superlattice period. The signal’s amplitude and phase modulation of the SL Bragg peaks induced by the lattice excitation i.e. the artificial THz phonon, are predominantly driven by electron pressure within the first picoseconds. This response is faster than the Debye-Waller effect, which is limited by the electron-phonon coupling time.

Keywords: ultrafast; x-ray diffraction; thermal transport; phonon