Regensburg 2019 – wissenschaftliches Programm
HL 45.30: Poster
Donnerstag, 4. April 2019, 18:30–21:00, Poster E
Photoinduced transient spin polarization in the semiconducting lead halide perovskite (CH3NH3)PbI3 above the orthorhombic-tetragonal phase transition — •Oskar Schuster1, Daniel Niesner1, Thomas Fauster1, Shreetu Shrestha2, Ievgen Levchuk2, Miroslaw Batentschuk2, and Christoph Brabec2 — 1Lehrstuhl für Festkörperphysik, Univ. of Erlangen–Nürnberg, Staudtstr. 7, D-91058 Erlangen — 2I-MEET, Univ. of Erlangen–Nürnberg, Martensstr. 7, D-91058 Erlangen
(CH3NH3)PbI3 belongs to a class of semiconducting lead halide perovskites with singly degenerate valence and conduction band, playing an important role in current solar cell research. At 160 K the material undergoes a transition from a centrosymmetric orthorhombic phase to a tetragonal phase which is centrosymmetric on average, exhibiting local disorder. The concept of a "dynamical Rashba effect" induced by the local electric fields in the disordered structure has been proposed by theoretical models and by measurements of optically induced spin currents . For the disordered, high–temperature phase a transient magneto–optical Kerr effect (MOKE) is induced by pumping the fundamental optical transition with circularly polarized light. A clear MOKE signal is absent in the ordered, low-temperature phase. This further supports the idea of a "dynamical Rashba effect". We discuss the picosecond spin dynamics and the possible spin scattering mechanisms in this new class of Rashba semiconductors.
 D. Niesner et al., Proc. Natl. Acad. Sci. 115, 9505 (2018)