Wannier excitons in the ferromagnetic semiconductors EuO and EuS

Journal Article · Mon Sep 15 04:00:00 EDT 1975 · Phys. Rev., B, v. 12, no. 6, pp. 2311-2317

DOI:https://doi.org/10.1103/PhysRevB.12.2311· OSTI ID:4142563

Mitani, T; Koda, T

Fine structures in the thermoreflectance (TR) spectra of EuO and EuS in the ultraviolet region are ascribed for the first time to Wannier excitons in magnetic semiconductors. The characteristic temperature-induced splittings of the spectra of EuO and EuS at the ferromagnetic spin-ordering temperatures are successfully analyzed in terms of the exciton and the spin-polarization effect of the relevant one-electron bands, an s-like conduction and p-like valence bands, at the GAMMA point. The magnetic-spin-exchange energies, J/subc/ and J/subv/, between the localized Eu-4f electrons and the band electrons, the spin-orbit interaction energy lambda for the valence band, and the electron-hole spin- exchange energy $delta$ for the exciton are estimated. It is demonstrated that the TR measurements open a new aspect of the optical study of magnetic- semiconductor excitons which become an ideal probe for directly detecting the interaction between the localized-magnetic-spin system and the nonlocalized-Bloch- electron system in the magnetic semiconductors.

• Research Organization: Department of Applied Physics, Faculty of Engineering, University of Tokyo, Hongo, Bunkyo-ku, Tokyo, 113 Japan
• NSA Number: NSA-33-001129
• OSTI ID: 4142563
• Journal Information: Phys. Rev., B, v. 12, no. 6, pp. 2311-2317, Journal Name: Phys. Rev., B, v. 12, no. 6, pp. 2311-2317; ISSN PLRBA
• Country of Publication: United States
• Language: English

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