Uniqueness and future perspectives of 2D ferroelectric devices: applications in emerging computing paradigms and hardware security.

Two-dimensional (2D) ferroelectric materials recently emerged as promising candidates for use in next-generation electronic and photonic applications. Distinct from their bulk counterparts, these atomically thin materials exhibit robust levels of ferroelectricity at monolayer thicknesses, diverse polarization orientations, and unique ferroionic behaviors. This review traces the evolution of the field-from early observations to modern polarization theory-using Landau-Ginzburg-Devonshire, soft-phonon, density-functional, and Berry-phase frameworks to clarify the microscopic origins of 2D ferroelectricity in van-der-Waals crystals and heterostructures. We then survey device-level demonstrations that leverage these unique dipoles for energy-frugal in-sensor computing, processing- and logic-in-memory architectures, and neuromorphic reservoir systems. A distinctive focus is placed on hardware security, where stochastic polarization switching enables true-random-number generators and physically unclonable functions. Future research directions focus on improved synthetic methods, device stability, and scalable integration strategies to expand the innovative applications of 2D ferroelectrics.