On 23 February, a two-page paper by Hideo Hosono of the Tokyo Institute of Technology and his coworkers appeared on the website of the Journal of the American Chemical Society. The TIT team reported that fluorine-doped lanthanum oxide iron arsenide superconducts at 26 K. 1
The value of T c is not especially high. But to the few physicists who noticed the paper, the new superconductor looked alluring. Like the high-T c cuprates, LaO1−x F x FeAs is a layered tetragonal compound containing a rare earth and oxygen. Unlike the cuprates, the new superconductor’s parent is a semimetal and its magnetic susceptibility is far higher.
Here, it seemed, was a material in which magnetic fluctuations, not phonons, mediate the electron pairing that underlies superconductivity. If that first impression proved true, Hosono and his team had discovered a new family of unconventional and possibly high-T...
