Regensburg 2022 – scientific programme
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HL: Fachverband Halbleiterphysik
HL 20: 2D Materials 4 (joint session HL/CPP/DS)
HL 20.3: Talk
Wednesday, September 7, 2022, 10:00–10:15, H36
Rashba excitons in the 2D Ruddlesden-Popper perovskite (BA)MAPI — •Philipp Moser1, Martin Schalk1, Atsuhiko Miyata2, Joachim Wosnitza2, Andreas Stier1, and Jonathan Finley1 — 1Walter Schottky Institute, Garching, Germany — 2Helmholtz-Zentrum Dresden-Rossendorf, Dresden, Germany
Two-dimensional organic-inorganic perovskites have emerged as remarkable materials for energy conversion, optoelectronic and spintronic applications. Recently, the role of spin-orbit (SO) coupling and the resulting effects on the band-structure and dark/bright optical transitions has become a key topic of interest. The necessary structural inversion asymmetry for SO-coupling is predicted to stem from the organic cations comprising the crystals. As a result, dark excitons, red detuned from the bright exciton, have been discussed in this material system. Here, we investigate the exciton physics of the 2D Ruddlesden-Popper perovskite (BA)MAPI. By performing one-photon absorption, -PL and two-photon PLE spectroscopy, we investigate the optical transitions close to the R-point of the Brillouin zone and find distinct 2-photon transitions blue detuned from the ground state exciton that can be explained by a Rashba-split band-structure. Utilizing high-field magneto-spectroscopy up to B=60T, we determine that these absorption features are due to Wannier excitons. We determine the size and binding energy from the diamagnetic shift of the features and obtain evidence that 2D (BA)MAPI hosts strongly bound Rashba excitons.