Regensburg 2016 – scientific programme
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O: Fachverband Oberflächenphysik
O 94: Ultrafast Surface Dynamics II
O 94.5: Talk
Friday, March 11, 2016, 11:45–12:00, S054
Attosecond Delays in the Photoemission from the Layered Crystals Bi2Te3 and Non-Centrosymmetric BiTeCl — •Sergej Neb1, Christian Oberer1, Walter Enns1, Norbert Müller1, J. Hugo Dil2,3, Evgueni V. Chulkov4,5, Pedro M. Echenique4, Walter Pfeiffer1, and Ulrich Heinzmann1 — 1Universität Bielefeld, Germany — 2Paul-Scherrer-Institut, Villigen, Switzerland — 3Institute of Condensed Matter Physics, École Polytechnique Fédérale de Lausanne, Switzerland — 4Donostia International Physics Center (DIPC) and Unidad de Fisica de Materiales CSIC-UPV/EHU, Basque Country, Spain — 5Tomsk State University, Russian Federation
The availability of single attosecond (as) XUV pulses allows investigating ultrafast electron dynamics on the as time scale by recording slight temporal shifts of the photoelectron streaking in a simultaneously present strong IR field. The physical origin of the observed delays is not yet understood and controversial theoretical models coexist demonstrating our still limited understanding of the fundamentals of the photoemission process. Here we report on as-time-resolved photoemission from the layered crystals Bi2Te3 and non-centrosymmetric BiTeCl. The lack of inversion symmetry allows studying relative photoemission delays on differently terminated but well-defined surfaces. Due to reversed layer stacking, photoelectron propagation effects such as the mean free path and the internal effective potential can be determined. However, the measured relative delays cannot be explained by electron propagation alone. Hence effects beyond pure propagation through the layers influence the photoemission dynamics.