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HL: Fachverband Halbleiterphysik

HL 49: Optical Properties

HL 49.12: Vortrag

Donnerstag, 25. März 2010, 12:30–12:45, H14

Spin induced second harmonic generation in europium chalcogenides — Benjamin Kaminski¹, •Marco Lafrentz¹, Roman V. Pisarev², Dmitri R. Yakovlev^1,2, Victor V. Pavlov², Volodya A. Lukoshkin², Andre Henriques³, Gunther Springholz⁴, Günther Bauer⁴, Eduardo Abramof⁵, Paulo H. O. Rappl⁵, and Manfred Bayer¹ — ¹Experimentelle Physik II, Technische Universität Dortmund, D-44221 Dortmund, Germany — ²Ioffe Physico-Technical Institute, Russian Academy of Sciences, 194021 St. Petersburg, Russia — ³Instituto de Fisica, Universidade de Sao Paulo, 05315-970 Sao Paulo, Brazil — ⁴Institut für Halbleiter- und Festkörperphysik, Johannes Kepler Universität Linz, 4040 Linz, Austria — ⁵LAS-INPE, 12227-010 Sao Jose dos Campos, Brazil

The second harmonic generation (SHG) in Europium chalcogenides EuX (X=O, S, Se, and Te) is fordbidden in the electric dipole and the electric quadrupole approximations due to the centrosymmetrical crystal lattice and the electronic band structure with an odd parity 4f-5d band gap transition. However we have found SHG signals in the vicinity of the band gap of 2.2-2.4eV in EuTe and EuSe in external magnetic fields. Further magnetic field and temperature investigations revealed that the SHG signals are induced by a ferromagnetic spin component, which strongly enhances the magnetic-dipole transition. This new type of spin induced susceptibility opens access to various classes of centrosymmetric magnetic materials by second harmonic generation spectroscopy.