Time-of-flight momentum microscopy system

• Subject Area: Condensed Matter Physics
• Term: Funded in 2020
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 440842653

We request a time-of-flight momentum microscopy system that will be used for multiple time-resolved photoemission experiments planned in the group Experimentelle Physik VI - coherent spin phenomena in solids - that is currently being established at the TU Dortmund. The main goal of the group Experimentelle Physik VI is to control the magnetic and electronic properties of solids on the shortest possible length- and time-scales by minimizing energy dissipations, i.e. by means of coherent effects. This proposal will be submitted in parallel with a proposal for a femtosecond extreme ultraviolet source, that will be combined with the here requested time-of-flight momentum microscopy system to build a setup for time-resolved photoemission experiments. This combination will allow us to perform the cutting-edge angle- and time-resolved photoemission experiments that are planned in the ERC consolidator project hyControl as well as in the project of the DFG Collaborative Research Centre "Coherent manipulation of interacting spin excitations in tailored semiconductors". These projects require, on the one hand, to perform femtosecond molecular orbital mapping, and on the other hand to map the time evolution of the band structure of magnetically ordered 2D materials throughout the whole Brillouin zone with femtosecond time resolution. Such on-going research projects, as well as future research activity planned in the group, pose a set of demanding requirements on the time-of-flight momentum microscopy setup. More specifically, the setup should consist of two interconnected UHV chambers: one for sample analysis by time-of flight momentum microscopy, and the second one for sample preparation and characterization. The main component of the analysis chamber should be a highly efficient photoemission spectrometer with exceptional angular acceptance (180°) and parallel acquisition of the whole angular distribution of the photoelectrons together with their kinetic energy. This will allow us to record time-resolved photoemission data of the band structure in the whole Brillouin zone (including the pattern of molecular orbitals) with unprecedented quality and signal-to-noise ratio. At the same time it will be possible to circumvent space-charging effects, that typically reduce the energy- and momentum-resolution in time-resolved photoemission experiments. The setup should allow to perform the photoemission experiments at Helium temperature, since the magnetic interactions at hybrid interfaces and 2D materials studied in most of the projects are strongly temperature dependent. Finally, the preparation UHV chamber should allow to prepare different material systems in-situ and to perform standard surface-science characterization. Since the single components of this complex system should be perfectly matched to each other, it should be acquired as a complete system from a single company.

• DFG Programme: Major Research Instrumentation
• Major Instrumentation: System für Flugzeit-Impulsmikroskopie
• Instrumentation Group: 5130 Sonstige spezielle Elektronenmikroskope
• Applicant Institution: Technische Universität Dortmund
• Leader: Professor Dr. Mirko Cinchetti