The International Cooperative Research team consisted of Professor Iwasa
and PhD student Takano (Institute for Materials Research, Tohoku
University), Chief Researcher Takata (RIKEN Spring-8 Center) and other
coworkers found that in Cs3C60 is not superconducting at ambient
pressure and is free from disorder, unlike the well-studied
face-centered cubic A3 C6, where the molecular vanences 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. A 15 Cs3C60 is an ideal material for
understanding the interactions producing superconductivity in
structurally an d chemically complex orrelated electron systems such as
the cuprates and oxyarsenides, as it allows the isolation of the
influence of only electronic factors (including orbital degeneracy)
without any other complications. This research achievement was published
American Science Journal 'Scuence' on online version on 20 March, 2009.

[Contact]
Professor Iwasa Yoshihiro
Institute for Materials Research, Tohoku University
Phone: +81 22-215-2030
FAX：+81 22-215-2031
e-mail：iwasa_AT_imr.tohoku.ac.jp (Replace _AT_ to @)