Microscopic parameters of the van der Waals CrSBr antiferromagnet from microwave absorption experiments

Microwave absorption experiments employing a phase-sensitive external resistive detection are performed for a topical van der Waals antiferromagnet CrSBr. The field dependence of two resonance modes is measured in an applied field parallel to the three principal crystallographic directions, revealing anisotropies and magnetic transitions in this material. To account for the observed results, we formulate a microscopic spin model with a bi-axial single-ion anisotropy and inter-plane exchange. Theoretical calculations give an excellent description of full magnon spectra enabling us to precisely determine microscopic interaction parameters for CrSBr.Comment: includes a supplementary information documen

Faits pour servir à l'histoire des eaux sulfureuses, par Hector Aubergier,...

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Microscopic parameters of the van der Waals CrSBr antiferromagnet from microwave absorption experiments

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Quantum plasmonics and hyperbolic material for biosensing

International audienceIn this work, we demonstrate that it is possible to use III-V semiconductors for plasmonics from the THz up to the midinfrared spectral range. We have fabricated hyperbolic nano-antenna based on heavily doped semiconductors demonstrating localized plasmon modes. This hyperbolic nano-antenna is 10 times: 10 nm doped InAs / 10 nm undoped GaSb. The free carriers are confined in the 10 nm layer of InAs. The confinement shifts the effective plasma frequency of the metamaterial towards the high frequencies, extending the possibility to probe molecules until 2000 cm-1 , thus covering the complete fingerprint frequency range for molecular and biosensing applications. The nano-structuration of the hyperbolic material allows to access two main plasmonic resonances at 800 cm-1 and 2000 cm-1. This bimodal property is appealing to detect and identify biomolecules over a large spectral range. With these hyperbolic nanoantennas, we can either enhance the absorption of rovibrational modes of molecules with surface-enhanced infrared absorption (SEIRA) spectroscopy 1 or enhance the thermal emission of molecules with surface-enhanced thermal emission spectroscopy (SETES) 2