Regensburg 2010 – wissenschaftliches Programm
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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. Yakovlev1,2, 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.