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

Area of Science:

• Condensed Matter Physics
• Materials Science
• Spintronics

Background:

• Recent experiments observed unconventional out-of-plane dampinglike torque in WTe2/Permalloy systems.
• Spin-orbit torque in 2D materials is crucial for next-generation spintronic devices.

Purpose of the Study:

• To theoretically investigate spin-orbit torque in two-dimensional transition metal dichalcogenide (TMD)/ferromagnet heterostructures.
• To understand the origin of dampinglike torques in these systems.

Main Methods:

• First-principles calculations.
• Linear response theory.
• Spin current flux calculations.

Main Results:

• Calculated significant dampinglike torkances in WTe2/Co and MoTe2/Co heterostructures.
• Observed both conventional and novel dampinglike torques with comparable magnitudes.
• Found good agreement between calculated torque and spin current flux.

Conclusions:

• The conventional model of spin-orbit torque (spin Hall effect + spin transfer torque) largely applies to TMD/Co bilayers.
• These findings provide insights into the fundamental mechanisms of spin-orbit torque in 2D material heterostructures.