Intrinsic Rashba\nEffect in Stable Configurations of\nTwo-Dimensional (PEA)<sub>2</sub>PbI<sub>4</sub>

Halide\nperovskites (HPs) are crystalline solids that\nfeature a\nunique softness, absent in conventional semiconducting materials.\nIn recent years, this softness has been pivotal to many properties\nin these materials, in both static and dynamic regimes. Here, we focus\non the two-dimensional (2D) (PEA)<sub>2</sub>PbI<sub>4</sub> crystal.\nWe employ extensive density functional theory calculations and structural\nanalysis to uncover a rich mosaic of ground-state configurations,\nidentifying several stable configurations with distinct electronic\nproperties. Our study uncovers an intrinsic Rashba effect within a\nstructure traditionally considered as globally centrosymmetric, presenting\na challenge to conventional understanding in the field. The observed\neffect emerges from a local symmetry-breaking induced by specific\nspatial orientations of the organic PEA molecules. This intrinsic\nRashba effect, observed in select configurations, underscores the\nnuanced symmetrical complexities of 2D HPs and highlights their potential\nfor spin-related applications. Additionally, our investigation demonstrates\nthe exceptional flexibility of 2D HPs, as evidenced by an observed\nsignificant tolerance toward single-molecule rotations. This flexibility\nsuggests potential pathways for smoother transitions between different\nmolecular domains within these materials. Overall, our findings emphasize\nthe intricate interplay between the organic/inorganic counterparts\nand the electronic properties in 2D HPs, paving the way for further\nexploration and exploitation of their unique characteristics in various\noptoelectronic and spintronic applications.