Regensburg 2019 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 36: II-VI- and III-V-semiconductors

HL 36.3: Vortrag

Donnerstag, 4. April 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)