Giant Tunneling Electroresistance up to 108% via Synchronous Ohmic–Schottky Switching at Dual Interfaces in Ti2CF2/Bilayer GaN Sliding Ferroelectric Tunnel Junctions

Ferroelectric tunnel junctions (FTJs) based on sliding ferroelectrics hold promise for next-generation nonvolatile memories, yet achieving a high tunneling electroresistance (TER) ratio remains challenging. In this work, the Ti2CF2/bilayer GaN sliding FTJ is theoretically constructed, and its electronic transport properties are explored using density functional theory (DFT) combined with nonequilibrium Green's function (NEGF) formalism. Our calculations reveal that ferroelectric polarization reversal in bilayer GaN modulates interfacial work function differences, enabling reversible transitions between Ohmic and Schottky contacts at both vertical and lateral interfaces. In the P↑ state, dual Ohmic contacts yield a high-conductance ON state. In contrast, the P↓ state produces large Schottky barriers at both interfaces that suppress tunneling current, corresponding to an OFF state. This dual-interface Ohmic-Schottky switching mechanism yields an ultrahigh TER ratio of up to 108%. Our findings provide critical insights into interface engineering and material selection for ultrahigh-TER FTJ devices based on sliding ferroelectrics.