Ferroelectric Control of Polarity of the Spin-polarized Current in Van Der Waals Multiferroic Heterostructures

Ferroelectric (FE) control of magnetism at nanoscale, for instance, FE control of the polarity of spin-polarized current is crucial for technological advances in magnetoelectric and spintronic applications. However, this fascinating functionality has not been reported in nanoscale systems yet. Herein, a new class of FE/A-type antiferromagnetic heterobilayer/FE van der Waals (vdW) multiferroic structures is found, in which the FE control of polarity of spin-polarized current is found possible. Take Sc₂CO₂/CrSiTe₃/CrGeTe₃/Sc₂CO₂ heterostructure as a successful example. First-principles calculations reveal that its polarity of half-metallicity can be switched by flipping the FE polarization orientation. Meanwhile, device transport simulation shows that its up/down spin current transmission ratio is as large as 0.1 × 10³ at $\overrightarrow{\mathrm{P}}\uparrow \uparrow$ Sc₂CO₂ configuration and is only 2.6 × 10⁻³ at $\overrightarrow{\mathrm{P}}\downarrow \downarrow$ Sc₂CO₂ configuration in the vdW multiferroic heterostructures. Essentially, it stems from the reversible FE switch of the internal electric field across the CrSiTe₃/CrGeTe₃ heterobilayer and the FE control of the interfacial effect between Sc₂CO₂ and Cr(Si/Ge)Te₃ layers. This work opens a direction for constructing low-energy-dissipation, non-volatile, and high-sensitive spintronic devices such as spin field-effect transistors.