Electronic properties of K-doped C60(111): Photoemission and electron correlation.

High-resolution photoemission provides the signatures of K 3 C 60 (111), K 4 C 60 , K 6 C 60 , and the dilute solid solution of K in C 60 (111), showing the effects of electron-electron correlation in all of the K-C 60 phases. K 3 C 60 (111) is a metal with a distinct Fermi-level cutoff but with spectral broadening near E F not predicted by band calculations. K 4 C 60 is an insulator, although band calculations predict metallic character. Photoemission and low-energy-electron-diffraction results demonstrate kinetically limited growth for K-C 60 films produced by vapor deposition