Modulation of the Dresselhaus-like spin current in a geometrically asymmetric WS2/Co/Pt trilayer

Abstract

Spin currents with their direction of polarization collinear to the current, termed Dresselhaus-like spin currents, have garnered significant attention recently. This type of spin current can break the symmetry of the magnetic order and drive efficient magnetization switching by the current in devices with in-plane magnetic anisotropy. In this study, we utilize an in-plane geometrically asymmetric device with 2H-WS₂/Co/Pt trilayers to modulate the Dresselhaus-like spin current. We break the in-plane magnetic symmetry by applying a voltage in the out-of-plane direction, and characterize the amplitude of the Dresselhaus-like spin current using the antisymmetric second-harmonic Hall signal. This signal scales linearly with both the applied electric and magnetic fields, similar to the nonlinear planar Hall effect. Experiments demonstrated that the Dresselhaus-like spin current originates from the in-plane geometrically asymmetric 2H-WS₂, which interacts with Co together with the conventional y-polarized spin current originating from Pt. Our findings complement the understanding of spin currents in transition-metal dichalcogenides/ferromagnetic heterostructures due to charge-to-spin conversion and provide new ideas for the design of magneto-resistive random-access memory.