Graphene/Ni(111) System: Spin- and Angle-Resolved Photoemission Studies

TL;DR

This study investigates the electronic and spin properties of graphene on Ni(111), revealing a Rashba effect that enables potential control of electron spin in graphene-based spintronic devices.

Contribution

It demonstrates the spin-dependent energy splitting of graphene's π states on Ni(111), highlighting the Rashba effect as a mechanism for spin control in graphene.

Findings

Graphene acts as a protective layer on Ni(111), preventing oxidation.

A significant spin splitting of up to 225 meV in graphene's π band was observed.

The splitting is attributed to the Rashba effect, enabling spin manipulation.

Abstract

Here we report spin- and angle-resolved photoemission studies of the inert graphene layer formed on the surface of a ferromagnetic material, Ni(111). X-ray photoemission and spin-resolved spectroscopy of secondary electrons reveal that graphene behaves like a protection layer on the Ni(111) surface preventing its reaction with adsorbed oxygen. Angle-resolved photoelectron spectroscopy of $\pi$ states of graphene on Ni(111) shows a strong dependence of binding energy of these states on the direction of magnetization of the sample. We conclude that the observed extraordinary high "splitting" up to 225 meV of the $\pi$ band in the graphene layer is a manifes-tation of the Rashba effect which provides a direct possibility to a flexible control of an electron spin in a graphene-based spin-FET.