Researchers at Japan’s Tohoku University claim to have discovered an entirely new state of matter. The new material has a rare combination of properties—it is a metal, a magnet, an insulator, and a superconductor. When this new material was studied using infrared spectroscopy, the molecules show distortions that have only been known to occur in insulators. On the other hand, nuclear magnetic resonance measurements also show conductivity. It has therefore been dubbed a “Jahn–Teller metal,” after the Jahn-Teller effect, which relates geometrical deformations among molecules and ions to a material’s electrical properties. The new material is not only interesting because it is a new state of matter, but especially because of the exciting possibility that it is a high-temperature superconductor.
The Tohoku team developed the new material by using rubidium, a strange alkali metal element, to change the amount of space between buckyballs, a pure carbon structure. They have shown that applying pressure (in this case, by chemically changing the distances between molecules) can increase the conductivity of a material that is an insulator at lower pressures. While pressure is applied, the molecules maintain their old shapes, so there is an overlap where the material looks like an insulator but acts like a conductor, because electrons move freely. This strange state of matter could help researchers understand high-temperature superconductors, which have endless possibilities for electronics design in the future.