Synchrotron radiation photoemission spectrum study on K 3 C 60 film

K 3 C 60 , single crystal film was prepared on the cleaved (111) surface of C 60 , single crystal. Synchrotron radiation angle-resolved photoemission spectra were measured at normal emission with sample temperature at × 150K. Up to four subpeaks of LUMO-derived band were observed. These sub-peaks exhibit distinct energy dispersions which resemble in general the theoretical ones calculated for K 3 C 60 at low temperature with the so-called one-dimensional disordered structure. But there is large deviation of experimental sub-band intervals from the theoretical values. This result is meaningful for the studies of the physical properties of alkali-doped C 60 solids, e.g. the mechanism for superconductivity.