Abstract
Recently synthesized two-dimensional (2D) van der Waals (vdW) ferromagnets, FexGeTe2 (x =4 and 5), have attracted great attention due to their room-temperature Curie temperature. By using ab initio noncollinear-spin quantum transport simulations, we predict a monotonic increasing tendency of the tun-neling magnetoresistance (TMR) with increasing theta (the angle between the spins of the two electrodes) in FexGeTe2/graphene/FexGeTe2 vdW magnetic tunnel junctions (MTJs). The calculated maximal TMR of the two MTJs is up to 7000% and 1100% for x = 4 and 5, respectively, and the former is even nearly 6 times larger than that of the commonly used MgO-based MTJ (1000% at 5 K) owing to nearly perfect spin polarization. The calculated maximal spin-transfer torque per voltage is 1-2 orders of magnitude larger than that of the MgO-based one, resulting in a reduction in the critical current for magnetization reversal by a factor of 4-5. Such high-performance 2D FexGeTe2-based (x = 4 and 5) MTJs are promising for next-generation room-temperature nonvolatile memories.