Magnetic exciton of EuS revealed by resonant inelastic x‑ray scattering

Authors

Lucia Amidani, Jonas J. Joos, Pieter Glatzel, Jindřich Kolorenč

Laboratory / Department
Department of Condensed Matter Theory
Citation
Physical Review Letters 134 (2025) 046401.
DOI
10.1103/PhysRevLett.134.046401
Year
2025

Together with scientists from the European Synchrotron (ESRF), we revisit an old problem of interpretation of sharp features observed in the optical absorption spectra of europium chalcogenides like EuO and EuS. It remained open since the 1970s, whether these features correspond to narrow europium 5d bands [1] or whether they are due to excitons (electron-hole pairs) localized at the europium atoms [2]. In our study, we use resonant inelastic x-ray scattering (RIXS) in combination with first-principles electronic structure theory to demonstrate that the exciton scenario applies. We show that the RIXS spectra contain clear signatures of wide europium 5d bands and localized excitons in the same time, which validates the conjecture of Kasuya and collaborators.

More details in Spotlight on Science at ESRF.

RIXS spectrum of EuS compared to optical absorption
(a) Experimental RIXS, (b) comparison of the optical absorption spectrum with the RIXS integrated along the incident-energy axis, and (c) calculated RIXS including the dipole (Eu 5d → Eu 2p) and quadrupole (Eu 4f → Eu 2p) emission. The features labeled A and B are localized excitons, feature C corresponds to europium 5d band.
  1. P. Wachter, The optical electrical and magnetic properties of the europium chalcogenides and the rare earth pnictides, Crit. Rev. Solid State Sci. 3 (1972) 189.
  2. T. Kasuya, S-f exchange interactions and magnetic semiconductors, Crit. Rev. Solid State Sci. 3 (1972) 131.
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