Photoemission, from core levels and valence band, and low-energy electron diffraction (LEED) have been employed to investigate the electronic and structural properties of graphene-ferromagnetic (G-FM) systems, obtained by intercalation of one monolayer (1 ML) and several layers (4 ML) of Co on G grown on Ir(111). Upon intercalation of 1 ML of Co, the Co lattice is resized to match the Ir-Ir lattice parameter, resulting in a mismatched G/Co/Ir(111) system. The intercalation of further Co layers leads to a relaxation of the Co lattice and a progressive formation of a commensurate G layer lying on top. We show the C 1s line shape and the band structure of G in the two artificial phases, mismatched and commensurate G/Co, through a comparison with the electronic structure of G grown directly on a Co thick film. Our results show that while the G valence band mainly reflects the hybridization with the d states of Co, regardless of the structural phase, the C 1s line shape is very sensitive to the rumpling of the G layer and the coordination of carbon atoms with the underlying Co. Even in the commensurate (1 × 1) G/Co phase, where graphene is in register with the Co film, from the angular dependence of the C 1s core level we infer the presence of more than a single component, due to inequivalent adsorption sites of carbon sublattices.

Electronic structure of graphene/Co interfaces

PACILE', Daniela;Papagno M;Pisarra M;
2014-01-01

Abstract

Photoemission, from core levels and valence band, and low-energy electron diffraction (LEED) have been employed to investigate the electronic and structural properties of graphene-ferromagnetic (G-FM) systems, obtained by intercalation of one monolayer (1 ML) and several layers (4 ML) of Co on G grown on Ir(111). Upon intercalation of 1 ML of Co, the Co lattice is resized to match the Ir-Ir lattice parameter, resulting in a mismatched G/Co/Ir(111) system. The intercalation of further Co layers leads to a relaxation of the Co lattice and a progressive formation of a commensurate G layer lying on top. We show the C 1s line shape and the band structure of G in the two artificial phases, mismatched and commensurate G/Co, through a comparison with the electronic structure of G grown directly on a Co thick film. Our results show that while the G valence band mainly reflects the hybridization with the d states of Co, regardless of the structural phase, the C 1s line shape is very sensitive to the rumpling of the G layer and the coordination of carbon atoms with the underlying Co. Even in the commensurate (1 × 1) G/Co phase, where graphene is in register with the Co film, from the angular dependence of the C 1s core level we infer the presence of more than a single component, due to inequivalent adsorption sites of carbon sublattices.
File in questo prodotto:
Non ci sono file associati a questo prodotto.

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/20.500.11770/148810
 Attenzione

Attenzione! I dati visualizzati non sono stati sottoposti a validazione da parte dell'ateneo

Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus 43
  • ???jsp.display-item.citation.isi??? 44
social impact