Regensburg 2019 – scientific programme
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O: Fachverband Oberflächenphysik
O 85: Ultrafast Electron Dynamics at Surfaces and Interfaces II: New Methods and Developments
O 85.3: Talk
Thursday, April 4, 2019, 15:30–15:45, H16
Measuring spin polarization and attosecond time delay in photoemission: current possibilities and perspectives — •Mauro Fanciulli1,2, David Bresteau2, Jakub Schusser1, Zakariae El Youbi1, Olivier Heckmann1, Christine Richter1, Thierry Ruchon2, and Karol Hricovini1 — 1LPMS, Université de Cergy-Pontoise, France — 2LIDYL, CEA Saclay, France
The phase term of the photoemission matrix elements is related to both the Wigner time delay of the process and to the spin polarization of photoelectrons from spin-degenerate states in the presence of spin-orbit coupling. Thus it is possible to make an estimate of the photoemission time scale by measuring the spin polarization [1].
In the first part of the talk, the model [2] that allows to indirectly access attosecond (as) time delays with spin-resolved experiments will be reviewed. In the second part, current attempts to combine spin resolution with direct femtosecond (fs) and as time resolution will be presented. We have installed an angle-resolved photoemission spectroscopy setup with a 3D VLEED spin detector at the recent Attolab beamline of CEA Saclay. The beamline provides a 10 kHz IR fs laser and a XUV laser based on high-harmonic generation. This give us the unique possibility to perform spin-resolved fs pump-probe and reconstruction of as-beating by interference of two-photon transitions (RABBIT) experiments on solid targets, with the aim of studying the spin polarization of the photoelectrons at their fundamental time scale.
[1] M. Fanciulli et al., PRL 118, 067402 (2017) [2] M. Fanciulli and H. Dil, arXiv:1806.05895 (2018)