Giant electrode effect on tunneling magnetoresistance and electroresistance in van der Waals intrinsic multiferroic tunnel junctions using VS2

Abstract

Van der Waals multiferroic tunnel junctions (vdW-MFTJs) with multiple nonvolatile resistive states are highly suitable for new physics and next-generation storage electronics. However, currently reported vdW-MFTJs are based on two types of materials, i.e., vdW ferromagnetic and ferroelectric materials, forming a multiferroic system. This undoubtedly introduces additional interfaces, increasing the complexity of experimental preparation. Herein, we engineer vdW intrinsic MFTJs utilizing bilayer VS${}_2$. By employing the nonequilibrium Green's function combined with density functional theory, we systematically investigate the influence of three types of electrodes (including non-vdW pure metal Ag/Au, vdW metallic 1T-MoS${}_2$/2H-PtTe${}_2$, and vdW ferromagnetic metallic Fe${}_3$GaTe${}_2$/Fe${}_3$GeTe${}_2$) on the electronic transport properties of VS${}_2$-based intrinsic MFTJs. We demonstrate that these MFTJs manifest a giant electrode-dependent electronic transport characteristic effect. Comprehensively comparing these electrode pairs, the Fe${}_3$GaTe${}_2$/Fe${}_3$GeTe${}_2$ electrode combination exhibits optimal transport properties, the maximum TMR (TER) can reach 10949\% (69\%) and the minimum resistance-area product (RA) is 0.45 $\hat{I}\text{c◯}$$\hat{I}¼$m${}^2$, as well as the perfect spin filtering and negative differential resistance effects. More intriguingly, TMR (TER) can be further enhanced to 34000\% (380\%) by applying an external bias voltage (0.1 V), while RA can be reduced to 0.16 $\hat{I}\text{c◯}$$\hat{I}¼$m${}^2$ under the influence of biaxial stress (-3\%). Our proposed concept of designing vdW-MFTJs using intrinsic multiferroic materials points towards new avenues in experimental exploration.

13 pages, 9 figures