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MA: Fachverband Magnetismus

MA 40: Weyl Semimetals

MA 40.1: Talk

Friday, September 9, 2022, 09:30–09:45, H48

Magneto-optical detection of topological contributions to the anomalous Hall effect — •Felix Schilberth^1,2, Nico Unglert³, Lilian Prodan¹, Christine Kuntscher⁴, Liviu Chioncel³, and Sándor Bordács² — ¹Experimentalphysik V, Augsburg University, Augsburg, Germany — ²Department of Physics, BME Budapest, Hungary — ³Theoretische Physik III, Augsburg University, Augsburg, Germany — ⁴Experimentalphysik II, Augsburg University, Augsburg, Germany

The anomalous Hall effect (AHE) is a profound manifestation of non-trivial band structure topology in magnetic materials. The ambiguous separation of its intrinsic and extrinsic contributions leads to a fundamental limitation in identifying topological states based on common magnetotransport experiments. Here we demonstrate, via a case study on the prominent topological kagome magnet Fe₃Sn₂, that the intrinsic contribution to AHE can be determined unambiguously from the broadband spectrum of the optical Hall effect, obtained by energy-resolved magneto-optical Kerr-effect (MOKE) measurements. Using MOKE spectroscopy complemented with material-specific theory, we identified the interband excitations responsible for the intrinsic AHE. We found that low-energy transitions, tracing "helical volumes" in momentum space reminiscent of the formerly predicted helical nodal lines, substantially contribute to the AHE, which is further increased by contributions from multiple higher-energy interband transitions. Our calculation also shows that local Coulomb interactions lead to important band reconstructions near the Fermi level.