Excellent spin-filtering and giant tunneling magnetoresistance in a dual-electrode van der Waals magnetic tunnel junction based on ferromagnetic CrSe2

Magnetic tunnel junctions (MTJs) both with efficient spin-filtering effect and large tunneling magnetoresistance (TMR) ratio are extremely attractive and highly desirable in the field of spintronics. Inspired by recent successful preparation of a stable two-dimensional (2D) layered ferromagnet 1 T-CrSe 2 on a 2H-WSe 2 substrate via chemical vapor deposition (CVD) synthesis, herein, employing first-principles calculations, we investigate the spin-dependent transport properties of van der Waals (vdW) MTJs built with a monolayer 2H-WSe 2 tunnel barrier and a 1 T-CrSe 2 single-electrode or a 1 T-MoSe 2 /1 T-CrSe 2 dual-electrode. Compared to low TMR (67.3%) in single-electrode MTJ, dual-electrode MTJ exhibits excellent spin-filtering effect (with 99.96% spin polarization) and a giant TMR ratio (up to 2.29 × 10 5 %), which mainly originates from the half-metallicity of CrSe 2 induced by charge transfer at MoSe 2 /CrSe 2 interface. Relatively high TMR values (over 1 × 10 3 %) are always maintained at small bias voltages (| V b | ≤ 0.35 V). Our work have for the first time theoretically verified feasibility of realizing the transition of 2D CrSe 2 from metallicity to half-metallicity in the vdW MTJ and yielding excellent spin-filtering and giant magnetoresistance via electrode interface engineering, thereby providing important theoretical guidance for the experimental design of high-performance vdW MTJs in spintronic devices. • . A huge magnetoresistance up to 2 × 10 5 % is realized in dual-electrode MTJ based on 1 T-CrSe 2 monolayer. • . Electrode interface engineering renders half-metallicity of CrSe 2 and nearly 100% spin polarization of dual-electrode MTJ. • . High magnetoresistance (over 10 3 %) is maintained at small bias voltage (| V b | ≤ 0.35 V).