Modification of the valence band electronic structure under Ag intercalation underneath graphite monolayer on Ni(111)

TL;DR

This study investigates how silver intercalates beneath a graphite monolayer on Ni(111) and how this affects the valence band structure, revealing a weakening of the chemical bonding between the graphite and substrate.

Contribution

It provides detailed experimental insights into the intercalation process of silver and its impact on the electronic structure of graphite on Ni(111).

Findings

Silver intercalates beneath graphite upon annealing at 350-450 C.

Intercalation causes a shift in the valence band towards higher energies.

The bonding between graphite and Ni(111) weakens due to silver intercalation.

Abstract

Angle-resolved photoemission spectroscopy and Auger electron spectroscopy have been applied to study the intercalation process of silver underneath a monolayer of graphite (MG) on Ni(111). The room-temperature deposition of silver on top of MG/Ni(111) system leads to the islands-like growth of Ag on top of the MG. Annealing of the "as-deposited" system at temperature of 350-450 C results in the intercalation of about 1-2 ML of Ag underneath MG on Ni(111) independently of the thickness of pre-deposited Ag film (3-100 A). The intercalation of Ag is followed by a shift of the graphite-derived valence band states towards energies which are slightly larger than ones characteristic for pristine graphite. This observation is understood in terms of a weakening of chemical bonding between the MG and the substrate in the MG/Ag/Ni(111) system with a small MG/Ni(111) covalent contribution to this interaction.