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HL: Fachverband Halbleiterphysik
HL 39: 2D semiconductors VII – CrSBr and related heterostructures
HL 39.3: Vortrag
Donnerstag, 12. März 2026, 10:00–10:15, POT/0081
Exciton dominated anisotropic dielectric tensor in CrSBr — •Jan-Hendrik Larusch1, Pierre-Maurice Piel1, Aleksandra Łopion1, Thomas Kliewer1, Zdeněk Sofer2, and Ursula Wurstbauer1 — 1Institute of Physics, University of Münster, Germany — 2Department of Inorganic Chemistry, University of Chemistry and Technology Prague, Prague, Czech Republic
CrSBr is an air-stable magnetic vdW semiconductor with a direct bandgap; its anisotropic spin, lattice, and charge, drive anisotropic light-matter interaction ε(ω). We directly determine the full dielectric tensor of exfoliated CrSBr by spectroscopic imaging ellipsometry (SIE). In the paramagnetic phase, SIE verifies εxx×εyy×εzz. Room-temperature comparison of Mueller-matrix and generalized ellipsometry guides cryogenic SIE, enabling us to track changes across the Curie and Néel temperatures as the system evolves from paramagnetic over intralayer ferromagnetism to A-type antiferromagnetism. In the AFM phase, polarization-resolved magneto-reflectance with fields along c (hard), b (easy), and a (intermediate) axis yields critical fields of roughly 2.2, 1.05, and 0.3 T for transition to FM order sensed by distinct optical fingerprints. Together, these measurements quantify the anisotropic light-matter interaction and its dependence on magnetic order, linking exciton-dominated emission/absorption to the full dielectric tensor [1]. [1] J. Klein et al. ACS Nano 17, 5316-5328 (2023).
Keywords: CrSBr; dielectric function; anisotropy; magnetic semiconductor; reflectance