Transport properties of multiferroic tunnel junctions based on sliding ferroelectric VTe2

Multiferroic tunnel junctions (MFTJs), characterized by a ferroelectric barrier encapsulated between two ferromagnetic electrodes, represent a highly promising platform for next-generation nonvolatile memory applications. The recent discovery of intrinsic ferromagnetism and ferroelectricity in van der Waals (vdW) materials further provides a compelling material foundation for constructing multifunctional MFTJs based on vdW heterostructures. In this paper, aiming at high-performance and multifunctional van der Waals multiferroic tunnel junctions (vdW-MFTJs) devices, we investigate the spin-dependent transport properties of vdW-MFTJs with a bilayer VTe2 sliding ferroelectric barrier and Fe3GaTe2/Fe3GeTe2 magnetic electrodes by using first-principles calculations based on density functional theory (DFT). Our results reveal that multiple non-volatile resistance states can be achieved by controlling the polarization direction of the ferroelectric barrier and the magnetization configuration of the ferromagnetic electrodes in the Fe3GaTe2/bilayer VTe2/Fe3GeTe2 MFTJs. Specifically, when the double-layer ferroelectric material VTe2 undergoes relative interlayer slippage, the polarization of the ferroelectric barrier switches from a left-oriented state (P←) to a right-oriented state (P→). Consequently, the tunneling magnetoresistance (TMR) ratio at the Fermi level increases from 7.27×105% to 1.01×106%. Moreover, switching the magnetization configuration of the ferromagnetic electrodes from parallel alignment (M↑↑) to antiparallel alignment (M↑↓) leads to an almost twofold increase in the tunneling electroresistance (TER) ratio. Furthermore, nearly 100% spin filtering efficiency is observed in all four non-volatile resistance states of the MFTJs. These findings demonstrate that the engineered Fe3GaTe2/bilayer VTe2/Fe3GeTe2 MFTJs hold promising potential applications in multi-state non-volatile memory and spin filters, providing a versatile platform for developing multifunctional electronic devices.