Prof. Kosmas Prassides - Fullerene superconductivity: a personal ongoing voyage into the unexpected
Following the discovery of C60 (a quasi-spherical molecule with dimensions of ~1 nm) in 1985, the subsequent isolation and preparation of bulk crystalline samples of fullerenes—a set of hollow, closed-cage molecules consisting purely of carbon—from arc-processed carbon in 1990 sparked off a remarkable interdisciplinary research activity, encompassing diverse fields of chemistry, physics and materials science. The early research activity quickly culminated in 1991 in the synthesis of superconductors with stoichiometry A3C60 (A = alkali metal) and considerably enhanced superconducting transition temperatures, Tc, when compared with any other molecular system. This was followed by a long period during which the established fulleride chemistry failed to deliver new materials. Therefore the physical picture of fullerene superconductivity remained unaltered until 2008 when the discovery of Cs3C60 led to their rebirth and demonstrated their commonality with other classes of unconventional superconductors such as the cuprates and the iron chalcogenide/pnictide systems. Here I will attempt to trace the development of this field of science to date with emphasis on its current status and future prospects.