Momentum-Resolved Tunneling Modulation Induced Giant Multistate Resistance in Antiferroelectric Multiferroic Junction

Multiferroic tunnel junctions (MFTJs), integrating ferroelectric and ferromagnetic functionalities within a single nanoscale device, hold significant promise for nonvolatile, multistate memory and innovative computing paradigms. In conventional MFTJs, tunneling resistance modulation relies primarily on ferroelectric (FE) polarization switching, which alters interfacial electric fields and shifts the Fermi level of adjacent ferromagnetic electrodes. However, achieving high tunnel electroresistance (TER) through this approach demands strong built-in electric fields, which simultaneously hinder FE polarization switching, creating an intrinsic trade-off between reliable data reading and efficient writing. Here, we propose a dual mechanism that combines antiferroelectric (AFE) phase-transition modulation of the evanescent decay states with interfacial spin filtering based on Fe₃GaTe₂/bilayer-α-In₂Se₃/Fe₃GaTe₂ heterostructure. Beyond altering the electrostatic potential as in AFE-FE switching, the transitions between head-to-head type and tail-to-tail type AFE states preserve the centrosymmetric potential profile yet fundamentally modulate the momentum-resolved distribution of evanescent decay rates across the Brillouin zone. When integrated with perfect spin filtering at the Fe₃GaTe₂/α-In₂Se₃ interface, this mechanism yields a giant TER (∼7.6 × 10³%), over 4 times that of conventional FE-based MFTJs, and a TMR exceeding 6.8 × 10⁵%, enhanced by 2 orders of magnitude over typical MFTJs. These mechanisms resolve the performance trade-off in MFTJs, enabling six distinct nonvolatile resistance states at room temperature.