SEARCH Articles Figures Tables Composition dependence of the resistivity p x for thick films of Cbo doped with Na, K, Rb, and Cs. Points indicate where exposure to the alkali-metal source was stopped and x-ray and ultraviolet photoemission spectra were acquired to determine the concentration x. The labels indicate the known fulleride phases at 300 K. The minima in p x occur for stoichiometries corresponding to NaQCeo, K.iCeo and Cs,.,.Cfio. [Publishers Imprint] [Publishers Imprint]