Regensburg 2016 – scientific programme
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O: Fachverband Oberflächenphysik
O 86: Ultrafast Surface Dynamics I
O 86.3: Talk
Thursday, March 10, 2016, 15:30–15:45, S052
Non-thermal phonon distribution in out-of-equilibrium aluminium — •Lutz Waldecker1, Roman Bertoni1, Jan Vorberger2, and Ralph Ernstorfer1 — 1Fritz-Haber-Institut der Max-Planck-Gesellschaft — 2Max-Planck-Institut für Physik komplexer Systeme
The interaction between electrons and lattice vibrations is central to both ground state as well as out-of-equilibrium properties of solids. We apply an approach based on femtosecond electron diffraction to retrieve these interactions in laser-excited aluminium at various excitation conditions by measuring the temporal evolution of the atomic mean squared displacement. The data is described with a refined version of the two-temperature model, which is inspired by ab initio theory calculations and allows for transient non-thermal phonon distributions. Our work suggests that assuming thermal phonon distributions, i.e. employing a two-temperature model, can lead to systematic errors in the interpretation of time-resolved experiments.