Electronic structure study of KxC60 compounds with x > 6

✍ Scribed by A.J. Maxwell; P.A. Brühwiler; S. Andersson; N. Mårtensson; P. Rudolf

• Publisher: Elsevier Science
• Year: 1995
• Tongue: English
• Weight: 473 KB
• Volume: 247
• Category: Article
• ISSN: 0009-2614
• DOI: 10.1016/0009-2614(95)01206-1

✦ Synopsis

We present C 1 s X-ray absorption and photoemission results for K xC6o with x > 6, the so-called 'superfullerides'. These are the first measurements of the unoccupied valence band for these systems and confirm that more than six electrons can be transferred to each fullerene. We observe saturation of the K-to-C6o charge transfer, with part of the t~g LUMO + 1 orbital remaining unoccupied, so that fewer than 12 electrons are accepted per C6o molecule. This fullerene state exhibits metallic behaviour, while a transition to insulating behaviour is observed as lower charge states are formed by adding more C6o. The superfullerides appear to follow the pattern of strongly correlated solids.