Superconductivity at 117K in a Buckyball Crystal

Superconductivity at 117K in a buckyball crystal has been observed by Bertram Batlogg at Lucent Technologies. A crystal of C₆₀ molecules normally has a lattice spacing of 1.415 nm and becomes superconducting at a temperature of 18 K. But by obliging the crystal to conduct with holes instead of electrons (in a transistor-like setup) and by adding other molecular species to space out the buckyballs a bit, the superconductivity transition temperature can be raised.

Batlogg and his colleagues at Lucent, the University of Konstanz (Germany), and the ETH lab in Zurich, have tried a number of candidates; the best so far is a dopant consisting of tribromo-methane (Br₃CH) molecules, which nudges the C-60 molecules out to a spacing of 1.445 nm and a transition temperature of 117 K, in the same realm as the high-temperature ceramic superconductors (Schön et al., Science, published online, 30 August).