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MA: Fachverband Magnetismus
MA 4: Magnetic Heusler Compounds and Complex Magnetic Oxides
MA 4.6: Talk
Monday, March 18, 2024, 10:45–11:00, EB 107
Magnetic excitations beyond the single- and double-magnons — •Hebatalla Elnaggar1, Abhishek Nag2, Maurits Haverkort3, Ke-Jin Zhou2, and Frank de Groot4 — 1Sorbonne University - CNRS, Paris, France — 2Diamond Light Source, Didcot, UK — 3Heidelberg University, Heidelberg, Germany — 4Utrecht University, Utrecht, Netherlands
Conventional wisdom suggests that one photon that carries one unit of angular momentum (1ℏ) can change the spin angular momentum of a magnetic site with one unit (δMs = 1± 1ℏ) at most following the selection rules. This implies that a two-photon process such as 2p3d resonant inelastic X-ray scattering (RIXS) can change the spin angular momentum of a magnetic system with a maximum of two units (δMs = ± 2ℏ). Hereinwe describe a triple-magnon excitation in α-Fe2O3, which contradicts this conventional wisdom that only 1- and 2-magnon excitations are possible in a resonant inelastic X-ray scattering experiment [1]. We observe an excitation at exactly three times the magnon energy, along with additional excitations at four and five times the magnon energy, suggesting quadruple and quintuple magnons as well. Guided by theoretical calculations, we reveal how a two-photon scattering process can create exotic higher-rank magnons and the relevance of these quasiparticles for magnon-based applications.
References: 1- H. Elnaggar, et. al., Magnetic excitations beyond the single- and double-magnons, Nat. Commun. 14, 2749 (2023).
Keywords: Multi-magnons; Resonant inelastic X-ray scattering; Magnons in antiferromagnets