Intermolecular overlap geometry gives two classes of fulleride superconductor: electronic structure of 38 K Tc Cs3C60.
Superconductivity emerges for the A15 polymorph of the fulleride Cs3C60 upon compression to a pressure of approximately 4 kbar. Using density functional theory we study the bonding in the A15 phase as a function of unit cell volume comparing it to that in the fcc polymorph. We find that, despite its smaller packing density, the bcc-derived A15 phase has both a substantially wider bandwidth for the partially occupied t1u band and a higher density of states at the Fermi level. This result can be traced to the striking differences in the nature of the interanion Tc--the two sphere packings (body centered versus face centered) observed experimentally produce two electronically distinct classes of fulleride superconductors.
Darling
G R
GR
Department of Chemistry, University of Liverpool, Liverpool L69 7ZD, United Kingdom. darling@liv.ac.uk
Ganin
A Y
AY
Rosseinsky
M J
MJ
Takabayashi
Y
Y
Prassides
K
K