Tremendous Tunneling Electroresistance and Magnetoresistance in a Two-Dimensional Sc₂CO₂/FeBr₂ Multiferroic Heterojunction Realized by Interfacial Charge Engineering

A van der Waals (vdW) multiferroic tunnel junction (MFTJ) with tunneling electroresistance (TER) and tunneling magnetoresistance (TMR) effects has emerged as a promising candidate for nonvolatile and multifunctional memory devices. However, simultaneously achieving giant TER and TMR ratios still faces significant hurdles. Here, a Sc₂CO₂/FeBr₂ multiferroic heterostructure is theoretically designed. A reversible transition from a semiconductor to half-metal for the FeBr₂ layer and invertible switching between a semiconductor and metal for the Sc₂CO₂ layer are realized, which is ascribed to the ferroelectric-controlled interfacial charge reconfiguration. Accordingly, the Sc₂CO₂/FeBr₂-based MFTJ using an FeBr₂ monolayer as a channel achieves a tremendous TER ratio of 2.6 × 10¹²% and TMR ratio of 4.4 × 10⁹%, accompanied by a perfect spin injection efficiency. Intriguingly, when Sc₂CO₂ is used as the tunneling barrier, the MFTJ exhibits an ultrahigh TER exceeding 10¹⁶% at the bias voltage. Our study provides valuable insights into the design of high-performance nanoscale spintronic devices leveraging interfacial effects.