Van der Waals Multiferroic Tunnel Junctions

Multiferroic tunnel junctions (MFTJs) have aroused significant interest due to their functional properties useful for nonvolatile memory devices. So far, however, all of the existing MFTJs have been based on perovskite-oxide heterostructures limited by a relatively high resistance-area (RA) product unfavorable for practical applications. Here, using first-principles calculations, we explore spin-dependent transport properties of van der Waals (vdW) MFTJs which consist of two-dimensional (2D) ferromagnetic FenGeTe2 (n = 3, 4, 5) electrodes and 2D ferroelectric In2Se3 barrier layers. We demonstrate that such FemGeTe2/In2Se3/FenGeTe2 (m, n = 3, 4, 5; m ≠ n) MFTJs exhibit multiple nonvolatile resistance states associated with different polarization orientation of the ferroelectric In2Se3 layer and magnetization alignment of the two ferromagnetic FenGeTe2 layers. We find a remarkably low RA product (less than 1 Ω·μm2) which makes the proposed vdW MFTJs superior to the conventional MFTJs in terms of their promise for nonvolatile memory applications.