2D ferroelectric materials: Emerging paradigms for next-generation ferroelectronics

Ferroelectric materials with electrically switchable spontaneous polarization are technologically important for developing next-generation low-power nanoelectronics and ferroelectronics. Regardless of significant challenges for rich functionalities owing to the insulating nature of conventional thin-film ferroelectrics, ferroelectricity instability or disappearance below a critical thickness limit generally exists. Therefore, exploring emerging two-dimensional (2D) ferroelectric materials with nanoscale dimensions and moderate bandgaps is crucial for developing high-integration functional nanoelectronics. This review offers a comprehensive analysis of the historical background and progression in both thin-film ferroelectrics and novel 2D ferroelectrics. Special attention is given to the device applications based on the emerging 2D ferroelectrics, in which the polarization switching process occurs within the channel material itself. Leveraging the switchable polarization in nanoscale 2D ferroelectrics, rationally designed device configurations with intriguing working mechanisms have been rapidly developed in various application scenarios, such as gate-tunable memristors, non-volatile memories, biological synapses, in-memory computing, etc. This review also sheds light on the potential opportunities and challenges in the future advancement of integrating novel 2D ferroelectric materials into devices within commercial electronic circuits.