Fullerides in a Squeeze

摘要

Before the discovery of cuprate superconductors, superconducting metals and Mott insulators-would-be metals turned insulating by repulsion between electrons-seemed to have nothing to do with one another. Yet in cuprates, superconductivity popped up by simply doping Mott insulators with some impurities (see the figure, panels A and B), opening up perhaps the most controversial physics field of the past 25 years. As Takabayashi et al. show on page 1585 of this issue (1), pressure works very much the same feat in a completely different material: the hyperexpanded body-centered-cubic A15-structured fulleride Cs_3C_(60), an insulator that is turned into a superconductor by giving it a light squeeze.