Giant optical orientation of exciton spins in lead halide perovskite crystals

Abstract

Optical orientation of carrier spins by circularly polarized light is the basis of spin physics in semiconductors. Here, we demonstrate strong optical orientation of 85\%, approaching the ultimate limit of unity, for excitons in FA${}_{0.9}$Cs${}_{0.1}$PbI${}_{2.8}$Br${}_{0.2}$ lead halide perovskite bulk crystals. Time-resolved photoluminescence allows us to distinguish excitons with 60~ps lifetime from electron-hole recombination in the spin dynamics detected via coherent spin quantum beats in magnetic field. We reveal electron-hole spin correlations through linear polarization beats after circularly polarized excitation. Detuning of the excitation energy from the exciton resonance up to 0.5~eV does not reduce the optical orientation, evidencing clean chiral selection rules in agreement with atomistic calculations, and suppressed spin relaxation of electrons and holes even with large kinetic energies.

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• The Landé factors of electrons and holes in lead halide perovskites: universal dependence on the band gap
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• Giant optical orientation of exciton spins in lead halide perovskite crystals

Cited by in corpus (2)

• Giant optical orientation of exciton spins in lead halide perovskite crystals
• Hyperfine interaction of electrons and holes with nuclei probed by optical orientation in MAPbI${}_3$ perovskite crystals