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HL: Fachverband Halbleiterphysik
HL 36: II-VI- and III-V-semiconductors
HL 36.3: Talk
Thursday, April 4, 2019, 10:00–10:15, H31
Second Harmonic Generation from the yellow 1S exciton in Cu2O in symmetry forbidden geometries — •Johannes Mund, Christoph Uihlein, Dietmar Fröhlich, Dmitri R. Yakovlev, and Manfred Bayer — Experimentelle Physik 2, Technische Universität Dortmund, Germany
We observe second harmonic generation (SHG) from the 1S exciton resonance of the yellow exciton series in Cu2O in four crystal orientations. For the light k-vector orientation parallel to [001] and [110] SHG should be symmetry forbidden [1]. The observed signals are explained by a band structure induced splitting of the 1S components and their mixing by residual strain in the samples. Measurements at the higher exciton resonances and a microscopic theory confirm that this effect can only be observed at the 1S exciton of relatively long lifetime, while the SHG of higher excited excitons is properly described by group theory.
[1] J. Mund et al., PRB 98, 085203 (2018)