Cuprate Superconductors May Be Conventional After All

C opper oxide superconductors, or “cuprates,” are the record holders for the highest critical temperature (Tc = 134 K) at ambient pressure. Among many applications, they might one day be used to make the tens of kilometers of cables that generate accelerating magnetic fields at CERN’s Large Hadron Collider. The origin of high-Tc superconductivity in cuprates, however, remains a major unsolved problem in physics. It is generally believed that the cuprates aren’t adequately described by the theory for ordinary superconductivity, the Bardeen-CooperSchrieffer (BCS) theory, since typically these materials do not exhibit features predicted by the theory. Now, a team led by Christoph Renner at the University of Geneva, Switzerland, has demonstrated that a model cuprate hosts vortex states that are a crucial feature of BCS behavior [1]. The finding, they argue, suggests that superconductivity in cuprates is of the conventional type.