Efficient Spin-Orbit Torque Generation in Semiconducting WTe2 with Hopping Transport

Spin-orbit torques (SOTs) from transition metal dichalcogenide systems (TMDs) in conjunction with ferromagnetic materials are recently found to be attractive in spintronics for their versatile features. However, most of the previously studied crystalline TMDs are prepared by mechanical exfoliation, which limits their potentials for industrial applications. Here, we show that amorphous WTe2 heterostructures deposited by magnetron sputtering possess a sizable damping-like SOT efficiency of xi(WTe2)(DL9) approximate to 0.20 and low damping constant of alpha = 0.009 +/- 0.001. Only an extremely low critical switching current density of J(c) approximate to 7.05 x 10(9) A/m(2) is required to achieve SOT-driven magnetization switching. The SOT efficiency is further proved to depend on the W and Te relative compositions in the co-sputtered W100-xTex samples, from which a sign change of xi(WTe2)(DL) is observed. In addition, the electronic transport in amorphous WTe2 is found to be semiconducting and is governed by a hopping mechanism. With the above advantages and rich tunability, amorphous and semiconducting WTe2 serves as a unique SOT source for future spintronics applications.

Automated summary

Recent research shows that amorphous WTe2 heterostructures deposited by magnetron sputtering exhibit high SOT efficiency and low damping constant, allowing for extremely low critical switching current density. The SOT efficiency is found to depend on the relative compositions of W and Te in the co-sputtered samples.