AVS 66th International Symposium & Exhibition
    Frontiers of New Light Sources Applied to Materials, Interfaces, and Processing Focus Topic Thursday Sessions
       Session LS+AC+HC+SS-ThA

Invited Paper LS+AC+HC+SS-ThA8
Time-Resolved Photoemission with Free-Electron Lasers

Thursday, October 24, 2019, 4:40 pm, Room A210

Session: Emerging Methods with New Coherent Light Sources
Presenter: Kai Rossnagel, CAU Kiel / DESY, Germany
Correspondent: Click to Email
Photoelectron spectroscopy is an essential analytical tool for learning about the properties and workings of quantum materials and functional interfaces, in which electrons are the main actors. In practice, photoelectron spectroscopy is a toolbox comprising three major techniques, where the momentum selectivity and atomic-site specificity of valence and core electron emissions are exploited, respectively: Angle-resolved photoelectron spectroscopy (ARPES) is the most powerful imaging technique for the energy-momentum space of the active electrons near the Fermi level, while x-ray photoelectron spectroscopy (XPS) is a universal tool for chemical analysis and x-ray photoelectron diffraction (XPD) an established surface structural probe. A dream is to combine all three techniques into a single experiment, make it complete by adding spin and femtosecond time resolution, and thus be able to shoot femto-stroboscopic movies of intertwined electronic, magnetic, chemical, and geometric structure dynamics and gain previously unachievable, direct “in operando” insight into dynamic structure-function relationships of materials and interfaces. Here, we aim to realize this dream by combining the soft x-ray SASE3 free-electron-laser (FEL) beam at the European XFEL with the most advanced photoelectron detection scheme currently available: the time-of-flight momentum microscope with efficient 3D energy-momentum detection and 2D spin filtering. The status of the project and of FEL-based photoelectron spectroscopy in general will be presented.