Regensburg 2022 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 34: Poster Tuesday: Scanning Probe Techniques 2
O 34.8: Poster
Dienstag, 6. September 2022, 11:00–13:00, P3
Setup for laser-based time-resolved momentum microscopy — •Felix Paßlack, Stefano Ponzoni, Giovanni Zamborlini, and Mirko Cinchetti — Department of Physics, TU Dortmund University, Otto-Hahn-Straße 4, Dortmund, Germany
In this work, we characterize the performance of a recently installed time-resolved angular-resolved photoemission spectroscopy (tr-ARPES) system. trARPES is performed by coupling an optical beamline for pump-probe spectroscopy[1] to a state-of-the-art momentum-microscopy photoemission spectrometer (KREIOS MM, SPECS GmbH). This allows for an almost continuous tunability of the pump photon energy between 0.5 eV and 3.8 eV while capturing the full photoemission horizon of the 6 eV probe. The performance of the system is characterized through a set of measurements on the topological insulator Bi2Se3, for which both the static electronic structure and the out of equilibrium electron dynamics are already extensively studied in literature following the evolution of the electronic structure with an energy resolution in the order of 50 meV, a momentum resolution of 0.005 A−1and a time resolution below 500 fs throughout the whole photoemission horizon. In particular, thanks to the ultimate angular acceptance of the photoemission microscope, we are able to track the dispersion of the photoexcited states in Bi2Se3 up to ± 0.48 A−1 and 1 eV above the Dirac point, beyond the practical limitations of conventional high-resolution ARPES spectroscopy with 6 eV photons. [1] F. Mertens et al., Review of Scientific Instruments 91 (2020)