Multilevel resistance states in van der Waals multiferroic tunnel junctions based on In 2 Se 3 /CuInP 2 S 6 ferroelectric heterostructures

Multiferroic tunnel junction (MFTJ) integrating magnetic electrodes with semiconducting ferroelectrics (FEs) as central tunneling barrier holds great promise for next-generation nonvolatile memory. The emergence of room-temperature van der Waals ferromagnets (e.g., Fe3GaTe2) and FEs (e.g., α-In2Se3, CuInP2S6) renders the possibility of all-vdW MFTJ under ambient conditions. Here, we employ first-principles calculations combined with nonequilibrium Green’s function methods to explore spin-dependent transport in Fe3GaTe2/α-In2Se3/CuInP2S6/Fe3GaTe2 junctions. The α-In2Se3/CuInP2S6 dual FE heterojunction introduces an additional degree of freedom for band alignment and interfacial charge modulation under external electric field, dramatically enhancing tunneling electroresistance. We find that polarization reversal leads to a giant tunneling electroresistance exceeding 6.2 × 104 %, far surpassing conventional tunnel junction with a single barrier. Furthermore, adjusting the relative magnetization of Fe3GaTe2 electrodes yields a colossal tunneling magnetoresistance up to 5.8 × 106 % upon polarization reversal. These results demonstrate the feasibility of multiple resistance states in MFTJ through coupled electric and magnetic field control, establishing ferroelectric heterojunctions as a powerful route toward high-density, multifunctional memory technologies.