Ferroelectric Ga 2 O 3 ‐Enabled High‐Density Spintronic Memory via Nonrelativistic Spin Splitting

Abstract The effective electrical control of spin currents is pivotal for advancing next‐generation, high‐density storage technologies with multi‐level memory capabilities. However, conventional heavy metal‐based spin‐orbit torque approaches encounter limitations such as excessive power consumption, integration challenges, and reliability constraints. Herein, a strategy for regulating spin polarization by utilizing ferroelectric polarization is proposed to break the parity‐time ( PT ) symmetry of the adjacent antiferromagnetic (AFM) layer, enabling four‐state nonvolatile memory operation in the multiferroic tunnel junction (MFTJ). The first‐principles calculations of atomic‐scale engineering of FE bilayer Ga 2 O 3 (bi‐Ga 2 O 3 ) and complex band analysis revealed significant differences in the tunneling barriers between different phases. The optimized Au/bi‐Ga 2 O 3 /Au ferroelectric tunnel junction exhibits a large tunnel electroresistance ratio of 8890%. Studies on the magnetic ground state show that the polarization in AFE‐H Ga 2 O 3 can significantly disrupt the interlayer AFM ordering in CrI 3 , inducing a transition to ferromagnetic (FM) ordering. Concurrently, AFE‐T Ga 2 O 3 polarization modulates CrI 3 through spin‐orbit coupling, causing non‐relativistic spin splitting (NRSS). Therefore, the designed Au/bi‐Ga 2 O 3 /bi‐CrI 3 /Au MFTJ can exhibit quad‐state memory operation with a maximum tunnel electroresistance modulation ratio of 3156%. These findings provide the theoretical framework for developing high‐performance antiferromagnetic tunnel junctions with enhanced programmability and readout characteristics.