Formation of surface intercalation compounds at Gd(Dy)/graphite interfaces under thermal annealing

Angle-resolved valence-band and C 1s core-level photoemission was used to study growth of surface intercalation-like phases upon deposition of trivalent rare-earth metals (Dy and Gd) onto a (0 0 0 1) surface of single-crystalline graphite and highly oriented pyrolytic graphite and subsequent annealing at increasing temperatures, Tanneal.. It was found that the synthesis of the surface intercalation compounds (Tanneal.∼1100°C) undergoes a stage of carbide formation (Tanneal.∼900°C). It was concluded that after the high temperature annealing the Gd(Dy)/graphite interfaces reveal layered structure and can be described as thin layers (up to one monolayer) of surface intercalation-like compounds grown on the top of (1 1 1) surfaces of Gd- and Dy-dicarbides.