Journal: Science
Volume: 323
First page: 1585
Last page: 1590
Year: 2009
Link: http://www.sciencemag.org/cgi/content/abstract/sci;323/5921/1585
Authors: Takabayashi Yasuhiro, Ganin Alexey Y., Jeglič Peter, Arčon Denis, Takano Takumi, Iwasa Yoshihiro, Ohishi Yasuo, Takata Masaki, Takeshita Nao, Prassides Kosmas, Rosseinsky Matthew J.
The body-centered cubic A15-structured cesium fulleride Cs3C60 is not superconducting at ambient pressure and is free from disorder, unlike the well-studied face-centered cubic A3C60 alkali metal fulleride superconductors. We found that in Cs3C60, where the molecular valences are precisely assigned, the superconducting state at 38 kelvin emerges directly from a localized electron antiferromagnetic insulating state with the application of pressure. This transition maintains the threefold degeneracy of the active orbitals in both competing electronic states; it is thus a purely electronic transition to a superconducting state, with a dependence of the transition temperature on pressure-induced changes of anion packing density that is not explicable by Bardeen-Cooper-Schrieffer (BCS) theory.