Giant tunneling electroresistance and multistate data storage in two-dimensional ferroelectric tunnel junctions via polarization-anisotropy coupling

Achieving large tunneling electroresistance (TER) and multistate data storage is crucial for advancing two-dimensional (2D) ferroelectric tunnel junctions (FTJs) toward high-density nonvolatile memories. In this work, we propose a strategy that couples ferroelectric polarization with transport anisotropy to realize multistate data storage in 2D FTJs. As a concrete implementation, we design a van der Waals heterostructure composed of metallic goldene and out-of-plane ferroelectric In2Se3, and construct 2D FTJs based on this heterostructure. Density-functional theory combined with nonequilibrium Green's function calculations show that the interfacial contact in the goldene/In2Se3 heterostructure can be reversibly switched between Schottky and Ohmic types by reversing the ferroelectric polarization, yielding a giant TER ratio of up to 108%. More importantly, the cooperative effect of polarization reversal and transport anisotropy induces four distinct resistance states that can be switched directly without an additional erase step. Our proposal provides a viable pathway for realizing nanoscale 2D FTJs with ultrahigh storage density and simplified multistate memory operation.