Layer-dependent Landé g-factors of electrons, holes, and excitons in two-dimensional Ruddlesden-Popper lead halide perovskites

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Two-dimensional Ruddlesden-Popper lead halide perovskites provide a valuable platform for tailoring charge and spin properties through quantum confinement and reduced symmetry. While the electron and hole Landé g-factors in bulk lead halide perovskites exhibit a universal dependence on the band gap energy, their evolution in two-dimensional perovskites has remained largely unexplored. Here, the Zeeman splittings of electrons and holes in (PEA)₂MAₙ₋₁PbₙI₃ₙ₊₁ perovskites with the number of inorganic layers ovarying in the range n=1,...,8 are measured by means of the spin-flip Raman scattering and time-resolved Kerr rotation magneto-optical techniques. A systematic evolution of the electron and hole g-factors with decreasing layer thickness, which deviates from the universal bulk behavior and reveals confinement-driven trends similar to those observed in perovskite nanocrystals, is found. The experimental results are in good qualitative agreement with empirical tight-binding calculations. The exciton g-factors are evaluated from the Zeeman splittings of the exciton resonances in reflectivity measured in pulsed magnetic fields up to 55 T. These results provide comprehensive insight into the spin properties of two-dimensional lead halide perovskites and establish them as a tunable platform for engineering spin-dependent phenomena in quantum-confined semiconductors.