• Experimental sta...
• Spin resolving electron time-of-flight momentum microscope
• Wide-angle electron spectrometer
• High magnetic field chamber
• Ultra low temperature XMCD
• Photoionization chamber for free atoms and molecules
• Shot-to-shot wavelength spectrometer
• Photon-Ion-Spectrometer at PETRA III
• Sputter source for metallic clusters

UNIEXP Research Experimental stations open for collaborations Spin resolving electron time-of-flight momentum microscope  · 

Space-, time- and spin-resolved photoemission using time-of-flight momentum microscope

Photoemission spectroscopy (PES) is a powerful technique, which allows investigating the electronic properties of solid systems and molecules. When used in combination with high repetition rate free electron lasers in the XUV and soft X-ray regime such as FLASH (DESY, Hamburg) or with the table-top laser systems based on the high harmonic generation (HHG) it has a high potential for time-resolved PES. The possibility to use both X-ray and laser pulses with time duration of few tens of femtoseconds will allow to access ultrafast electronic phenomena, lattice dynamics and chemical reactions. The photo-emitted electrons carry all the information regarding the electronic states of the system in the photo-generated non-equilibrium state. To fully exploit this information, it is necessary to use very efficient detection schemes for the photoelectrons, such as a time-of-flight momentum microscope. The momentum microscope allows simultaneous detection of the entire band structure with unprecedented efficiency in the full surface Brillouin zone with up to 8 Å^-1 diameter and several eV binding energy range, resolving about 2.5x10⁵ voxels, or the angular pattern of core level photoelectrons, respectively, for each time step in a pump-probe experiment. The novel experimental approach envisioned here combines time- and momentum-resolved photoelectron, parallel spin detection, x-ray photoelectron spectroscopy (XPS), and x-ray photoelectron diffraction (XPD) into a single experiment and can directly probe and disentangle the fundamental interactions behind these different emergent properties.

Schematic of the photoemission ToF momentum microscope and some exemplary experimental results.

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Schönhense et. al., Ultramicroscopy 183, 19, (2017)
Medjanik et. al., Nat. Mater., 16, 615, (2017)
Elmers et. al., Phys. Rev. B, 94, 201403, (2016)
Kutnyakhov et. al., SCIENTIFIC REPORTS, 6, 29394, (2016)