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O: Fachverband Oberflächenphysik
O 41: Poster Session III: Poster to Mini-Symposium: Ultrafast surface dynamics at the space-time limit I
O 41.3: Poster
Tuesday, March 2, 2021, 10:30–12:30, P
Heavy fermion dynamics in semimetallic and insulating phases — •Chul-hee Min1, Michael Heber2, Simon Müller3, Lukas Wenthaus2, Steffen Palutke2, Dmytro Kutnyakhov2, Federico Pressacco2, Lenart Dudy4, Matthieu Silly4, Hendrik Bentmann3, Kiana Baumgärtner3, Woojae Choi5, Yong Seung Kwon5, Markus Scholz6, Friedrich Reinert3, and Kai Rossnagel1,2 — 1IEAP, CAU Kiel, Germany — 2DESY, Hamburg, Germany — 3EP7 and ct.qmat, University of Würzburg, Germany — 4Synchrotron-SOLEIL, Saint-Aubin, France — 5Dep. of EMS, DGIST, South Korea — 6EuXFEL, Schenefeld, Germany
Due to time–energy correlation, heavy fermion systems with hard-to-detect meV energy scales are expected to show relatively slow dynamics on ps time scales, which are relatively easy to measure. Using the free-electron laser FLASH, we have performed time-resolved pump-probe photoemission spectroscopy (PES) of mixed valent TmSe1−xTex at a probe photon energy where the photoionization cross-section of the localized 4f states is two orders of magnitude higher than the ones of the other states. The system consists of two magnetic 4f12 and 4f13 configurations in the ground state and can be tuned from a semimetallic to an insulating phase via x without destroying the periodicity of the Tm ions. Here, we present and discuss the transient dynamics of the 4f states near EF showing a remarkably strong dependence on x. Particularly, we identify a renormalized 4f peak whose time-domain signature is distinct from all other 4f multiplet peaks.