Polarization-controlled contact barriers enable giant tunneling electroresistance in van der Waals ferroelectric tunnel junctions

The regulation of tunneling electroresistance (TER) in two-dimensional (2D) ferroelectric tunnel junctions (FTJs) is crucial for their practical applications. In this Letter, we introduce an innovative approach to manipulate TER by altering the interfacial contact barrier through polarization-induced modifications in interface transport properties. A comprehensive analysis of the electronic structures within heterostructures, consisting of a metallic TaSe₂ monolayer and a ferroelectric Sc₂CO₂ layer, uncovers a dual modulation effect of ferroelectricity on both the Schottky barrier height and the interfacial tunneling barrier. This phenomenon substantiates the influence of polarization on charge carrier transport across the interface. Through calculations employing the non-equilibrium Green's function method, we reveal a significant TER ratio (⁠ $2.41×1013$%) in TaSe₂/Sc₂CO₂-based FTJs. Our findings illustrate that distinct tunneling resistance states can be achieved through polarization reversal, as predicted by the proposed mechanism. These insights enhance the understanding of polarization-mediated TER in 2D FTJs and provide a foundation for the design of next-generation electronic devices leveraging 2D ferroelectric materials.