Rashba-like Spin Textures in Graphene Promoted by Ferromagnet-Mediated Electronic Hybridization with a Heavy Metal

Area of Science:

• Spintronics
• Condensed Matter Physics
• Materials Science

Background:

• Epitaxial graphene/ferromagnetic metal (Gr/FM) heterostructures on heavy metals are promising for spintronics due to perpendicular magnetic anisotropy and Dzyaloshinskii-Moriya interaction (DMI).
• Understanding the microscopic origins of their properties is crucial for device development.

Purpose of the Study:

• To elucidate the origin of induced spin-orbit coupling (SOC) at Gr/FM interfaces on heavy metals.
• To investigate the relationship between SOC, interface properties, and DMI in these heterostructures.

Main Methods:

• Spin- and angle-resolved photoemission spectroscopy (SARPES).
• Density functional theory (DFT) calculations.

Main Results:

• Heavy metals induce strong SOC in the graphene layer via hybridization with the ferromagnetic metal.
• A Rashba-SOC effect with significant in-plane spin splitting (∼100 meV) was observed at the Gr/Co interface, linked to DMI.
• This SOC effect diminishes with increasing Co thickness, indicating electronic decoupling.

Conclusions:

• The interaction between heavy metals and graphene, mediated by the ferromagnetic layer, is the source of enhanced SOC in graphene.
• The observed Rashba-SOC at the Gr/Co interface is a key factor for DMI and chiral spin textures.
• These findings provide fundamental insights for designing advanced Gr-based spintronic devices.