By Andrew Grant
SAN ANTONIO — Superconductors are finally heating up. A recent experiment is raising hopes that for the first time in two decades, physicists have set a record high temperature at which a material can transport electrical current with no resistance.
The material, a compound of hydrogen and sulfur, must be compressed at extreme pressures to become superconducting. And the temperature at which it works is still very low: 190 kelvins (–83° Celsius). But confirmation of the finding, which was first reported in a paper posted online in December at arXiv.org, would bring physicists another step toward finding or fabricating a material that exhibits superconductivity at room temperature (roughly 300 kelvins). It would also redirect the efforts of many physicists who have been focusing on copper-based superconducting compounds called cuprates.