Dresden 2017 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 52: Nanostructures at Surfaces: Dots, Particles, Clusters
O 52.12: Poster
Dienstag, 21. März 2017, 18:30–20:30, P1C
Ultrafast vibration and cooling of ultrathin gold nanotriangles studied by ultrafast X-ray Diffraction — •J. Pudell1, A. von Reppert1, R. M. Sarhan1, F. Stete1, M. Reinhard1,4, M. Rössle1, W. Koopmann1, F. Zamponi1, N. Del Fatti2, A. Crut2, J. Koetz3, F. Liebig3, C. Prietzel3, and M. Bargheer1,4 — 1Institut für Physik, Universität Potsdam, Karl-Liebknecht-Str. 24-25, 14476 Potsdam, Germany — 2FemtoNanoOptics group, Institut Lumière Matière, Univ Lyon, Université Lyon 1, CNRS, 69622 Villeurbanne, France — 3Institut für Chemie, Universität Potsdam, Karl-Liebknecht-Str. 24-25, 14476 Potsdam, Germany — 4Helmholtz-Zentrum Berlin, Wilhelm-Conrad-Röntgen Campus, BESSY II, Albert-Einstein-Str. 15, 12489 Berlin, Germany
We study the vibrations and subsequent thermalization of ultrathin gold nanotriangles upon optical excitation of the electron gas by ultrafast x-ray diffraction (UXRD). Our measurements yield an accurate determination of the structural response of an asymmetric nanoparticle including amplitude and phase of the excited vibrational motion. The amplitude of the fastest mode with 3.6 ps period measures the instantaneous rise of electronic pressure and the phonon-pressure rising within 6 ps. Slower symmetric in-plane modes of the particle contribute less to the signal. The nanosecond relaxation time of the expansion yields a direct measure of heat flow out of the nano-object, which is limited by the molecular connection to the substrate. We report data recorded at the laser-driven Plasma X-ray Source (PXS) in Potsdam and at the XPP-KMC3 Beamline at the synchroton radiation facility Bessy II.