Investigation of epitaxial arrangement and electronic structure of aLa@C82film grown on anMoS2surface

Molecular arrangement and electronic structure of a La@C82 film epitaxially grown on an MoS2 surface have been studied using reflection high-energy electron diffraction and electron energy-loss spectroscopy ~EELS!. It was revealed that La@C82 molecules form a close-packed hexagonal lattice on a cleaved face of MoS2 with the intermolecular distance of 1.1360.03 nm. EELS of the La@C82 film in the valence excitation region indicated seven peaks coming from p→p* transitions together with the p-plasmon excitation. The absence of a distinct band gap means that the La@C82 epitaxial film is not semiconducting, but metallic or semimetallic. From the EELS result, we propose an electronic structure diagram of the La@C82 epitaxial film.