Berlin 2012 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 35: Poster Session II (Polymeric biomolecular films; Nanostructures; Electronic structure; Spin-orbit interaction; Phase transitions; Surface chemical reactions; Heterogeneous catalysis; Particles and clusters; Surface magnetism; Electron and spin dynamics; Surface dynamics; Methods; Electronic structure theory; Functional molecules)
O 35.92: Poster
Dienstag, 27. März 2012, 18:15–21:45, Poster B
Real-time observation of electron propagation in condensed matter — •Stefan Neppl1, Elisabeth M. Bothschafter1,2, Ralph Ernstorfer3, Adrian L. Cavalieri4, Johannes V. Barth1, Dietrich Menzel1, Reinhard Kienberger2, and Peter Feulner1 — 1TU München — 2Max-Planck-Institut für Quantenoptik — 3Fritz-Haber-Institut — 4CFEL
Photo-ionization with isolated attosecond (1 asec = 10−18 s) XUV pulses simultaneously dressed by a precisely timed NIR electric field is envisaged as a tool for probing the ultrafast dynamics of electrons in condensed matter [1]. Here we demonstrate the ability of this streaking technique for real-time probing the motion of photo-excited electrons in thin metal films as they traverse single atomic layers. By growing epitaxial layers of magnesium on a W(110) substrate, we are able to follow the time evolution of the XUV-induced photoelectron wave packets originating from the W4f and Mg2p core states and the joint conduction band with a time resolution of only a few attoseconds. Depending on the initial state character of the released electrons, we measure relative time delays in their emission ranging from 10 to 200 asecs, with different dependencies on the thickness of the overlayer. The results will be compared to corresponding streaking experiments performed on magnesium and tungsten single crystals
[1] Cavalieri et al. Nature 449, 1029 (2007)