ELECTRONIC-PROPERTIES OF K-DOPED C(60) (111) - PHOTOEMISSION AND ELECTRON CORRELATION

High-resolution photoemission provides the signatures of K3C60(111), K4C60, K6C60, and the dilute solid solution of K in C60(111), showing the effects of electron-electron correlation in all of the K-C60 phases. K3C60(111) is a metal with a distinct Fermi-level cutoff but with spectral broadening near E(F) not predicted by band calculations. K4C60 is an insulator, although band calculations predict metallic character. Photoemission and low-energy-electron-diffraction results demonstrate kinetically limited growth for K-C60 films produced by vapor deposition.