Interfacial work-function engineering for giant tunneling electroresistance in a Sc ₂ CO ₂ /Y ₂ CO ₂ van der Waals ferroelectric tunnel junction

Van der Waals ferroelectric tunnel junctions (FTJs) based on two-dimensional (2D) materials offer a promising platform for next-generation nonvolatile memory, yet achieving ultrahigh tunneling electroresistance (TER) remains a critical challenge. This work demonstrates a giant TER effect of 5.83 × 10⁹% in a vertically stacked FTJ comprising out-of-plane ferroelectric monolayers Sc₂CO₂and Y₂CO₂. First-principles calculations and quantum transport simulations reveal that the TER originates from interfacial work-function engineering. In the<i>P</i>_↓↓state, a substantial work-function difference (Δ<i>W</i>= 2.35 eV) drives significant charge transfer and yielding high conductance. Conversely, the<i>P</i>_↓↑configuration exhibits a smaller Δ<i>W</i>(0.85 eV), insufficient to overcome the Sc₂CO₂band gap. These findings not only propose Sc₂CO₂/Y₂CO₂as an exceptional candidate for high-performance memory devices but also establish a general interfacial design strategy for achieving colossal TER in low-dimensional ferroelectric systems.