K3C60: a strongly correlated metal with molecular disorder

This paper reports an ultra-violet photoemmision spectroscopy study on K3C60 in the temperature range 30–600 K. The experiment shows that the temperature dependence of the conduction band is consistent with the behaviour of a strongly correlated metal. In addition, the photoemission intensity near the Fermi edge decreases as the temperature is increased. This trend is similar to the vanishing behaviour of the quasi-particle weight predicted for strongly correlated metals with increasing disorder. The experimental evidence that the shoulder visible in the highest occupied molecular orbital region, unexpected on the basis of conventional band calculations, is coupled with the sharp peak at the Fermi level is also provided.