Robust Magnetoelectric Coupling in FeTiO₃/Ga₂O₃ Non-van der Waals Heterostructures

Magnetoelectric coupling represents a significant breakthrough for next-generation electronics, offering the ability to achieve nonvolatile magnetic control via electrical means. In this comprehensive investigation, leveraging first-principles calculations, we unveil a robust magnetoelectric coupling within multiferroic heterostructures (HSs) by ingeniously integrating a non-van der Waals (non-vdW) magnetic FeTiO₃ monolayer with the ferroelectric (FE) Ga₂O₃. Diverging from conventional van der Waals (vdW) multiferroic HSs, the magnetic states of the FeTiO₃ monolayer can be efficiently toggled between ferromagnetic (FM) and antiferromagnetic (AFM) configurations by reversing the polarization of the Ga₂O₃ monolayer. This intriguing phenomenon arises from polarization-dependent substantial interlayer electron transfers and the interplay between superexchange and direct-exchange magnetic couplings of the iron atoms. The carrier-mediated interfacial interactions induce crucial shifts in Fermi level positions, decisively imparting distinct electronic characteristics near the Fermi level of composite systems. These novel findings offer exciting prospects for the future of magnetoelectric technology.