Séminaire / Seminar – Magneto-optical spectroscopy on van-der-Waals antiferromagnet and topological semimetals – Florian Le Mardelé – 22/10/24

salle 22-32-201

Florian Le Mardelé – Laboratoire national des champs magnétiques intenses, Grenoble, Université Grenoble Alpes

Abstract
Magneto-optical spectroscopy focuses on the interaction between light and matter, with the magnetic field acting as a continuously adjustable external parameter. The magneto-optic response offers valuable information into the intrinsic properties of systems in their unperturbed states. As a historical example, Landau-level spectroscopy has provided crucial insights into the electronic band structure of semiconductors and semimetals [1]. I will illustrate this point with my recent study on the low-energy excitations of TlBiSSe, a textbook Dirac semimetal. Following this, I will highlight the important role that magneto-optic plays in the ongoing research of van der Waals magnets.
Specifically, I will discuss the detection of a novel type of collective excitation, called longitudinal magnons in FePSe₃ and FePS₃ followed by the study of the magnetic alloy Fe₁−xNixPS₃ in which magneto-optics allows us to track precisely the evolution of the
magnetic properties with respect to the alloy composition.

References
[1] G. Landwehr and E. I. Rashba. Landau Level Spectroscopy. ISSN. Elsevier Science,
2012.