title: The investigation of cobalt intercalation underneath epitaxial graphene on 6H-SiC(0 0 0 1).
abstract: The intercalation behaviour of cobalt underneath both epitaxial graphene monolayer and bilayer on 6H-SiC(0001) have been investigated by scanning tunneling microscopy (STM) and density functional theory (DFT). Upon deposition, cobalt atoms prefer to agglomerate into clusters on the epitaxial graphene. After annealing the sample to 850 °C, the intercalation of the adsorbed cobalt atoms into both monolayer and bilayer epitaxial graphene on SiC takes place, as observed by the atomically resolved STM images. Further studies based on DFT modeling and simulated STM images show that, resulting from the interplay between the intercalated cobalt atoms and the carbon layers sandwiching it, the most energetically favourable intercalation sites of cobalt atoms underneath monolayer and bilayer graphene differ. Furthermore, the results show energy barriers of 0.60 eV and 0.41 eV for cobalt penetration through mono-vacancy defects at monolayer and bilayer graphene.
authors.affiliation: Department of Physics, Zhejiang University, Hangzhou 310027, People's Republic of China. Collaborative Innovation Centre of Advanced Microstructure, Nanjing 210093, People's Republic of China.
authors.forename: Yuxi
authors.initials: Y
authors.lastname: Zhang
authors.forename: Hanjie
authors.initials: H
authors.lastname: Zhang
authors.forename: Yiliang
authors.initials: Y
authors.lastname: Cai
authors.forename: Junjie
authors.initials: J
authors.lastname: Song
authors.forename: Pimo
authors.initials: P
authors.lastname: He