In the effort to understand what causes superconductivity, researchers have to examine the differences between high-temperature superconductors (HTS). All HTSs are either copper or iron based, and these two families are fairly different. For example, when not a superconductor the copper-based materials are non-conductive, but the iron-based materials are conductive, above the critical temperature. The iron-based materials can also be magnetic, which may or not influence superconductivity. Researchers at Rice University, Kyoto University, and the Japan Synchrotron Radiation Research Institute have recently found something the families do share though; asymmetry within the superconductivity region.
It has already been observed in both families of HTSs that some properties are asymmetrical. Measuring from left to right will get you different data than measuring top to bottom. What the researchers found is that this asymmetry, or nematicity, exists even when the material expresses its superconductivity. The researchers also found that a pattern found on the phase diagram of copper HTSs, which plot out the changes in the material at different temperatures, appears to exist for iron HTSs as well. This pseudogap, as it is called, may be linked to the materials becoming superconductors, but more research will be needed to confirm that.
Finding nematicity in both families of high-temperature superconductors may be very important towards understanding exactly what causes superconductivity. Once we achieve that goal we may be able to start designing advanced superconductors that operate at room-temperature.