Phase evolution and electronic states ofRb-intercalated C60 single crystals

Abstract

Rb-intercalated C60 thin film was prepared on the cleaved (111) surface of C60 single crystal under the ultra-high-vacuum condition. Phase evolution was studied by the synchrotron radiation photoemission technique. The energy distribution curves for the solid solution phase, Rb1C60 and Rb3C60 phases were observed. After the Rb3C60 thin film with a thickness of nanometers has formed on the surface layers of the C60 single crystal, the excess depositions of Rb do not induce the bulk-like fcc to bct or bcc structure transitions at room temperature. The large size of C60 molecule offers the surface vacancies for the formations of Rb4C60 and Rb5C60 adsorption phases that are further verified by Rb 3d core-level photoemission measurements. Valence band photoemission results exhibit that the surface phases are metallic.