Intrinsic ferroelectric CuVP₂S₆ for potential applications in neuromorphic recognition and translation

Two-dimensional ferroelectric materials hold promises for non-volatile memory and integrated electronic circuits. However, direct synthesizing and understanding the ferroelectric mechanism of two-dimensional room-temperature ferroelectrics remains challenging. Here, we report the synthesis of intrinsic room-temperature ferroelectric CuVP₂S₆ via spatially confined chemical vapor deposition method, as demonstrated by second harmonic generation and piezoresponse force microscopy measurements. Importantly, we experimentally uncover the ferroelectric mechanism of CuVP₂S₆, which originates from the movement of Cu ions, as confirmed by scanning transmission electron microscopy. Additionally, we construct an optoelectronic CuVP₂S₆ synaptic device, which enables a smooth transition from optical character recognition to neural machine translation using a transformer architecture. Our study not only elucidates the ferroelectric mechanism of two-dimensional metal phosphorus sulfide compounds but also integrates optical character recognition and neural machine translation within a single material, offering significant opportunities for neuromorphic computing systems.