Multilevel resistance states in van der Waals multiferroic tunnel junctions above room temperature

Multiferroic tunnel junctions (MFTJs) comprised of magnetic electrodes and a ferroelectric tunnel barrier have been emerging as promising candidates for nonvolatile memory applications. The recently discovered above room-temperature van der Waals (vdW) ferromagnet Fe3GaTe2 and ferroelectric α-In2Se3 provides possibilities for constructing room-temperature vdW MFTJs. In this work, by using first-principles calculations, we investigate the spin-dependent transport in vdW MFTJs with structure of Fe3GaTe2/bilayer α-In2Se3/Fe3GaTe2. We predict a giant tunneling magnetoresistance (TMR) high up to 10 000% by switching the magnetic alignments of Fe3GaTe2 and tunneling electroresistance (TER) exceeding 300% by controlling the ferroelectric configurations of bilayer α-In2Se3 in the proposed MFTJs. Furthermore, by introducing interface asymmetry and inserting monolayer of h-BN on one interface, the TMR and TER ratios of the MFTJs can be substantially enhanced. In consequence, the multi-level resistance states can be achieved by applying magnetic and electric field in asymmetric MFTJs. Our results highlight full vdW MFTJs for their potential applications in spintronic devices, particularly in the field of multilevel nonvolatile memories.