Spin dynamics of excitons, exciton-polaritons, and charge carriers in metal halide perovskite semiconductors

• Applicant: Dr. Natalia Kopteva
• Subject Area: Experimental Condensed Matter Physics
• Term: since 2024
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 552699366

The project aims to study the spin dynamics of excitons, exciton-polaritons, and charged carriers in bulk lead-halide and lead-free perovskite semiconductors. The investigations will focus on the spin and energy level structure of excitons, the intrinsic spin relaxation mechanisms, and the role of structural anisotropy. The perovskite samples will be studied by a wide toolbox of optical and magneto-optical techniques: magneto-reflectivity, magneto-photoluminescence, time-resolved photoluminescence, pump-probe differential reflection, and resonant Brillouin scattering. The experiments will be performed with high spectral resolution at low temperatures in the range from 100 mK to 300 K and in external magnetic fields up to 17 T. We will measure the polarized emission to get insight into spin-related phenomena, such as optical spin orientation and spin relaxation The studied samples will be bulk crystals with different compositions: organic-inorganic and fully inorganic materials with varying band gap energy, as well as lead-free inorganic perovskites with an indirect band gap structure available in cooperation. A theoretical analysis of the exciton energy and spin level structure, as well as of the spin relaxation mechanisms will support our experimental findings. The gained knowledge will not only have the fundamental value for the spin physics in perovskite semiconductors but also allow us to make conclusions on (i) the band structure and mixing in perovskite crystals, (ii) the intrinsic spin relaxation mechanisms, (iii) the origin of light emission, (iv) the

• DFG Programme: Research Grants