Berlin 2012 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 92: Poster Session: II-VI Semiconductors & ZnO and related Materials

HL 92.11: Poster

Thursday, March 29, 2012, 16:00–19:00, Poster D

Nonlinear magneto-optical study of excitons in ZnO — •Marco Lafrentz¹, David Brunne¹, Benjamin Kaminski¹, Victor V. Pavlov², Roman V. Pisarev², Dmitri R. Yakovlev^1,2, Dietmer Fröhlich¹, and Manfred Bayer¹ — ¹Experimentelle Physik 2, Technische Universitaet Dortmund, D-44221 Dortmund, Germany — ²Ioffe Physico-Technical Institute, Russian Academy of Sciences, 194021 St. Petersburg, Russia

We show that application of magnetic field causes in bulk wurtzite ZnO the optical second-harmonic generation (SHG) at energies of 2s/2p(A/B)-excitons in the Voigt geometry for B⊥k∥[0001], where SHG should be forbidden in the electric-dipole (ED) approximation. Investigations of magnetic- and electric field, temperature and azimuthal dependencies of SHG intensity allow us to deduce that this phenomenon arises from the higher order magnetic field perturbation known as magneto-Stark effect for excitons. This pertubation transforms like an effective electric field and leads to admixture of exciton wave functions of different parity and thus to resonant SHG enhancement.