Phys. Rev. Lett. 68, 3924–3927 (1992)Band gap, excitons, and Coulomb interaction in solid C60Received 11 March 1992; published in the issue dated 29 June 1992 The band gap of solid C60 is found to be 2.3±0.1 eV. The on-site molecular C60 Coulomb interaction (U) as determined from the KVV C60 Auger spectrum is found to be 1.6±0.2 eV. This value of U is shown to lead to Frenkel-type molecular excitons in the 1.5–2 eV range. These results lead us to suggest that doped C60 should be considered as a highly correlated system with U/W comparable to that in high-Tc cuprates and that stoichiometric K3C60 is a Mott-Hubbard insulator with a gap of about 0.7 eV. © 1992 The American Physical Society URL:
http://link.aps.org/doi/10.1103/PhysRevLett.68.3924
DOI:
10.1103/PhysRevLett.68.3924
PACS:
79.60.Eq
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