Strong Anisotropic Spin-Orbit Interaction Induced in Graphene by Monolayer WS_{2}

Area of Science:

• Condensed matter physics
• Materials science
• Spintronics

Background:

• Spin-orbit interaction (SOI) is crucial for spintronics.
• Graphene's potential for spintronic applications is hindered by weak intrinsic SOI.
• Transition metal dichalcogenides (TMDs) are known to possess strong SOI.

Purpose of the Study:

• To investigate the induction of anisotropic SOI in graphene by monolayer tungsten disulfide (WS2).
• To compare the SOI induced by monolayer WS2 versus bulk WS2 in graphene.
• To determine the characteristics and magnitude of the induced SOI.

Main Methods:

• Fabrication of graphene-monolayer WS2 and graphene-bulk WS2 heterostructures.
• Magnetotransport measurements to probe spin-orbit effects.
• Theoretical analysis of weak antilocalization (WAL) curves.

Main Results:

• Monolayer WS2 induces significantly stronger anisotropic SOI in graphene than bulk WS2.
• Estimated spin-orbit energy (E_so) exceeds 10 meV.
• Experimental data is best explained by a dominant z→-z symmetric SOI and Kane-Mele SOI.

Conclusions:

• Monolayer TMDs are highly effective in inducing strong SOI in graphene.
• The findings suggest potential for novel spintronic devices utilizing graphene-TMD heterostructures.
• Elliot-Yafet mechanism and Kane-Mele SOI contribute to spin relaxation and transport properties.