An international team led by researchers at Princeton University has directly observed a surprising quantum effect in a high-temperature iron-containing superconductor.
This research was partially funded by the Gordon & Betty Moore Foundation.
Superconductors conduct electricity without resistance, making them valuable for long-distance electricity transmission and many other energy-saving applications. Conventional superconductors operate only at extremely low temperatures, but certain iron-based materials discovered roughly a decade ago can superconduct at relatively high temperatures and have drawn the attention of researchers.
Exactly how superconductivity forms in iron-based materials is something of a mystery, especially since iron’s magnetism would seem to conflict with the emergence of superconductivity. A deeper understanding of unconventional materials such as iron-based superconductors could lead eventually to new applications for next-generation energy-saving technologies.
The researchers probed the behavior of iron-based superconductors when impurities – namely atoms of cobalt – are added to explore how superconductivity forms and dissipates. Their findings led to new insights into a 60-year old theory of how superconductivity behaves. The study was published in the journal Physical Review Letters this week.
Adding impurities is a useful way to learn about the behavior of superconductors, said M. Zahid Hasan, the Eugene Higgins Professor of Physics at Princeton University, who led the research team. “It is like the way we probe the wave behavior of water in the lake by throwing a stone,” he said. “The way the superconducting properties react to the impurity reveals their secrets with quantum-level detail.”