Berlin 2024 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 80: Correlated Electrons: Poster
TT 80.31: Poster
Donnerstag, 21. März 2024, 15:00–18:00, Poster E
Optical conductivity of the kagome magnets FeSn and Fe3Sn2: search for Weyl cone and flat band excitations — •Jihaan Ebad-Allah1,2, Fabian Meggle1, Raphael Borkenhagen1, Lilian Prodan3, Vladimir Tsurkan3, Felix Schilberth3, István Kézsmárki3, and Christine Kuntscher1 — 1Experimentalphysik II, Universitat Augsburg, 86159 Augsburg, Germany — 2Department of Physics, University of Tanta, 31527 Tanta, Egypt — 3Experimentalphysik V, Center for Electronic Correlations and Magnetism, Institute for Physics, Universitat Augsburg, D-86135 Augsburg, Germany
Magnetic materials with kagome-lattice arrangement have recently attracted considerable interest due to their remarkable electronic and magnetic properties such as topological Weyl semimetal state, topological superconductivity, and anomalous Hall effect. Kagome magnets FeSn and Fe3Sn2 belong to this material class, where theoretical calculations predict the existence of flat bands, nodal points, and helical nodal-lines in the vicinity of the Fermi energy, which motivated us to search for their fingerprints in the optical conductivity. Thus, we performed temperature-dependent reflectivity measurements on single crystals of both compounds. Our results reveal a similar profile of the optical conductivity spectrum for both materials, namely, intraband contributions at low energy, a dip below 0.16 eV, and a pronounced absorption band at around 0.4 eV followed by an increase of σ1 towards higher energies. We relate the observed excitations to possible transitions between electronic bands predicted by theoretical calculations.
Keywords: Infrared spectroscopy; Kagome magnet; Weyl fermions; Flat band excitations; Electronic band structure