The restoration of metallicity in the high-temperature, cubic phase of Li 4 C 60 represents a remarkable feature for a member of the A 4 C 60 family (A= alkali metal), invariably found to be insulators. Structural and resonance technique investigations on Li 4 C 60 at T> 600 K, show that its fcc structure is associated with a complete (4 e−) charge transfer to C 60 and a sparsely populated Fermi level. These findings not only emphasize the crucial role played by lattice symmetry in fulleride transport properties, but also re-dimension the role of Jahn-Teller effects in band-structure determination.
American Physical Society
2 Feb 2007
Volume: 75 Issue: 8 Pages: 081401
Physical Review B