Localized states influence spin transport in epitaxial graphene

Area of Science:

• Condensed matter physics
• Materials science
• Spintronics

Background:

• Understanding spin transport in 2D materials is crucial for spintronic applications.
• Epitaxial graphene on silicon carbide (SiC) is a promising platform for spintronics.
• Interface effects, such as buffer layers, can significantly influence electronic and spin properties.

Purpose of the Study:

• To develop a spin transport model incorporating localized states.
• To investigate the influence of localized states on spin precession and relaxation in graphene.
• To explain discrepancies in charge and spin transport measurements in epitaxial graphene on SiC.

Main Methods:

• Development of a spin transport model for diffusive channels with coupled localized states.
• Application of the model to Hanle spin precession measurements.
• Analysis of measurements on monolayer epitaxial graphene and quasi-free-standing monolayer epitaxial graphene on SiC(0001).

Main Results:

• The model predicts an effective increase in spin precession frequencies and a reduction in spin relaxation times due to localized states.
• Analysis of experimental data supports the model's predictions.
• Discrepancies in diffusion coefficients and high spin relaxation times are explained by localized states from the SiC buffer layer.

Conclusions:

• Localized states at the graphene-SiC interface significantly impact spin transport properties.
• The developed model provides a framework for understanding spin dynamics in such systems.
• This work offers insights into optimizing graphene-based spintronic devices.