Nature: Last December Mikhail Eremets, Alexander Drozdov, and their colleagues at the Max Planck Institute for Chemistry in Mainz, Germany, posted a preprint reporting that hydrogen sulfide becomes a superconductor at a pressure of 1.5 million atmospheres and a record-high temperature of 203 K (−70 °C). The discovery is spurring researchers to replicate, understand, and improve on the results. So far only one team of researchers has reproduced the initial finding of the vanishing of electrical resistance in a hydrogen sulfide sample. None has yet reproduced the Mainz team's observation of the Meissner effect, in which the sample's internal magnetic field is zero despite the presence of an external field. Theorist Matteo Calandra of the Pierre and Marie Curie University in Paris and his colleagues proposed in April that the superconductivity of H2S is mediated by lattice vibrations, as is the case for the low-temperature superconductivity exhibited by mercury and other nonexotic materials.
