Berlin 2015 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 70: Structural Dynamics in Nanoscale Materials Probed by Ultrashort Electron Pulses
O 70.2: Poster
Mittwoch, 18. März 2015, 18:15–21:00, Poster A
Resolution studies on a compact femtosecond transmission electron diffractometer and phonon decay in single crystalline graphite — Christian Gerbig1, •Silvio Morgenstern1, Marlene Adrian1, Christian Sarpe1, Arne Senftleben1, Matthias Wollenhaupt2, and Thomas Baumert1 — 1University of Kassel, Institute of Physics (CINSaT), D-34132 Kassel, Germany — 2University of Oldenburg, Institute of Physics, D-26111 Oldenburg, Germans
Time-resolved diffraction, using x-ray or electron probes, has become a promising technique to directly provide insights into dynamics at the molecular level with ultrafast precision [1]. We study dynamical processes in single crystalline graphite by means of ultrafast electron diffraction in order to expand the understanding of phonon generation and decay mechanisms being essential for future carbon based electronic devices [2].
Our highly compact DC electron diffractometer is fully characterized by experiments and N-body simulations. At balanced conditions a temporal resolution of 200 fs along with high-definition diffraction is achieved for dynamical studies on graphite single crystals in a maintainable measurement time [3]. We further present generation and decay processes of incoherent as well as coherent phonons in graphite as a function of film thickness down to few-layer graphene.
[1] M. Chergui & A. H. Zewail, Chem. Phys. Chem. 10, 28 (2009).
[2] T. Kampfrath et al., Phys. Rev. Lett. 95, 187403 (2005).
[3] G. Sciaini & R. J. D. Miller, Rep. Prog. Phys. 74, 096101 (2011).