Spin-orbit proximity effect in graphene on metallic substrates: decoration vs intercalation with metal adatoms

TL;DR

This study uses density functional theory to compare how decoration and intercalation of metal adatoms affect the spin-orbit splitting in graphene on metal substrates, revealing that intercalation can significantly enhance the effect.

Contribution

It demonstrates that intercalation of adatoms can enhance spin-orbit splitting in graphene more effectively than decoration, providing insights for spintronics device engineering.

Findings

Intercalation preserves Dirac cone linearity better than decoration.

Intercalated G/Pt(111) shows larger spin-orbit splittings than defect-free structures.

Decoration suppresses graphene's π band linearity due to strong adatom interaction.

Abstract

The so-called spin-orbit proximity effect experimentally realized in graphene (G) on several different heavy metal surfaces opens a new perspective to engineer the spin-orbit coupling (SOC) for new generation spintronics devices. Here, via large-scale density functional theory (DFT) calculations performed for two distinct graphene/metal models, G/Pt(111) and G/Au/Ni(111), we show that the spin-orbit splitting of the Dirac cones (DCs) in these stuctures might be enhanced by either adsorption of adatoms on top of graphene (decoration) or between the graphene and the metal (intercalation). While the decoration by inducing strong graphene-adatom interaction suppresses the linearity of the G's $\pi$ bands, the intercalated structures reveal a weaker adatom-mediated graphene/substrate hybridization which preserves well-defined although broadened DCs. Remarkably, the intercalated G/Pt(111) structure exhibits splittings considerably larger than the defect-free case.