Ferroelectricity and Rashba effect in 2D organic–inorganic hybrid perovskites

2D hybrid perovskites with strong spin–orbit coupling (SOC) and structural asymmetry represent a new class of quantum materials that can potentially display coexisting ferroelectricity and Rashba spin splitting. Studies on these systems provide insight into the coupling between strain, spin, and electronic degrees of freedom, as well as symmetry and order parameters in the bulk and at the interfaces. We review design principles for ferroelectric hybrid perovskites with tunable band gaps, Rashba spin-split properties, and multiple polar axes. Different from traditional inorganic semiconductors, the composition and chirality of the organic cation, along with the strength of the coupling between the organic and inorganic components, play key roles in deciding the structural asymmetry that drives ferroelectricity and the spin orbit field.