Unconventional spin-orbit torque in transition metal dichalcogenide/ferromagnet bilayers from first-principles calculations

Abstract

Motivated by recent observations of unconventional out-of-plane dampinglike torque in \ch{WTe2}/Permalloy bilayer systems, we calculate the spin-orbit torque generated in two-dimensional transition metal dichalcogenide (TMD)-ferromagnet heterostructures using first-principles methods and linear response theory. Our numerical calculation of spin-orbit torques in \ch{WTe2}/Co and \ch{MoTe2}/Co heterostructures shows both conventional and novel dampinglike torkances (torque per electric field) with comparable magnitude, around $100\hslash /2e(\mathrm{\Omega }\cdot \mathrm{cm}{)}^{-1}$, for an electric field applied perpendicular to the mirror plane of the TMD layer. To gain further insight into the source of dampinglike torque, we compute the spin current flux between the TMD and Co layers and find good agreement between the two quantities. This indicates that the conventional picture of dampinglike spin-orbit torque, whereby the torque results from the spin Hall effect plus spin transfer torque, largely applies to TMD/Co bilayer systems.

11 pages, 7 figures. Published version

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• Advanced capabilities for materials modelling with Quantum ESPRESSO
• Spin Transfer Torques
• Spin-orbit torques in heavy metal/ferromagnet bilayers with varying strength of interfacial spin-orbit coupling
• Thickness dependence of spin-orbit torques generated by WTe2
• Intrinsic Spin Hall Conductivity of MoTe2 and WTe2 Semimetals
• Current-Induced Torques with Dresselhaus Symmetry Due to Resistance Anisotropy in 2D Materials
• Computation of intrinsic spin Hall conductivities from first principles using maximally-localized Wannier functions

Cited by in corpus (3)

• Spin-orbit torque characterization in a nutshell
• Efficient Spin-Orbit Torque Generation in Semiconducting WTe2 with Hopping Transport
• Staggered spin Hall conductivity