Hydrogen sulfide sets high-temperature superconducting record

Nature : Hydrogen sulfide, the colorless gas that smells of rotten eggs, has been coaxed into demonstrating a characteristic property of superconductivity at a record high temperature of 203 K (−70 °C). Last year, Mikhail Eremets of the Max Planck Institute for Chemistry in Mainz, Germany, and his colleagues had seen H₂S superconducting below 190 K when compressed at 1.5 million atm. At such extreme pressures, the gas compresses into a solid crystal. Now, at a pressure of 2 million atm, the H₂S exhibited a sudden increase in “magnetization signal” at 203 K. That increase occurs when the material prevents external magnetic fields from passing through it, a phenomenon known as the Meissner effect. Two other groups report that they have seen the same phenomenon but are waiting for Eremets’s team to publish first. The previous highest superconducting transition temperature, 135 K, was obtained in 1993 in a layered cuprate material.