Microscopic Insights into Magneto-optics and Magneto-transport in 2D Perovskites.

Two-dimensional (2D) perovskites host tightly bound excitons with a fine structure shaped by spin-orbit coupling and exchange interaction. In the prototypical 2D perovskite, (PEA)2PbI4, the dark exciton lies below two bright excitons and a gray state. In-plane magnetic fields split the bright excitons, polarize them longitudinally (L) and transversely (T) to the field, and hybridize them with gray and dark states, respectively. The impact of magnetic fields on exciton emission and diffusion has remained largely unexplored. Here, we investigate time- and temperature-resolved magneto-optics and magneto-transport of excitons in (PEA)2PbI4. We demonstrate that magnetic fields enhance emission from XT excitons and accelerate the transport of XL states. We trace this back to suppressed scattering of XT states into dark excitons, while XL states form highly mobile hot dark excitons. The acquired microscopic insights offer guidance for experimental studies on magneto-optics and magneto-transport in layered perovskites.