Berlin 2018 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 12: Ultrafast Electron and spin dynamics at interfaces II
O 12.11: Vortrag
Montag, 12. März 2018, 18:00–18:15, MA 005
Spin polarization and attosecond time delay in photoemission from condensed matter — •Mauro Fanciulli1,2, Henrieta Volfová3, Stefan Muff1,2, Andrew Weber1,2, Jan Minár4, Ulrich Heinzmann5, and Hugo Dil1,2 — 1École Polytechnique Fédérale de Lausanne (CH) — 2Swiss Light Source, PSI, Villigen (CH) — 3Ludvig Maximilians Universität München (DE) — 4University of West Bohemia, Pilsen (CZ) — 5Universität Bielefeld (DE)
Interfering channels in the photoemission matrix elements are at the origin of spin polarization of the photoelectron beam even when the probed initial state is not spin-polarized [1]. Thus the measurement of spin polarization by means of spin- and angle-resolved photoemission spectroscopy allows to have information on the interference process, and in particular on the phase-shift φs between the channels. An extension of the Eisenbud-Wigner-Smith (EWS) model of particle scattering allows to relate the attosecond time delay in photoemission to the phase term φ of the matrix elements [2].
It will be shown that φ is closely related to φs, and that it is possible to make an indirect estimate of EWS time delays from a (non-time-resolved) spin-resolved experiment [3]. After the description of the model, experimental studies performed at the Swiss Light Source on several condensed matter systems of interest will be presented [3,4].
[1] E. Tamura et al., PRL 59, 08934 (1987) [2] R. Pazourek et al., Rev. of Mod. Phys. 87, 03765 (2015) [3] M. Fanciulli et al., PRL 118, 067402 (2017) [4] M. Fanciulli et al., PRB 95, 245125 (2017)