Researchers Discover A New State Of Matter
by Janet Fang
Photo credit: Crystal structure of molecular fulleride superconductors, consisting of 60 carbon atoms arranged in a soccer ball, with alkali metal ions (blue spheres) occupying vacant interstitial holes / K. Prassides, Tohoku University
Solid, liquid, gas, and plasma. We encounter these states of matter — or the first three at least — in our everyday lives, but there’s a slew of other states that only occur under extreme conditions. And now, researchers studying a family of unconventional superconductors say they’ve discovered an entirely new state of matter: a metallic phase called the Jahn-Teller metal. These could be the molecular buildings blocks that make it possible to conduct electricity at high temperatures — an elusive, long-sought-after goal. The findings were published in Science Advances last month.
Metals are used to transmit electricity, but because of electrical resistance, energy ends up getting lost as heat. Superconductors, on the other hand, carry electricity without losing energy; electrons pair up and move throughout superconducting materials without resistance. But even then, these conventional superconducting materials require very, very cold temperatures nowhere near room temp.
Now, a large international team led by Kosmas Prassides of Tohoku University may have found a way for metal to conduct electricity at higher temperatures without losing heat. According to a news release, the team investigated a superconductor that consist of alkali metal ions and molecules with 60 carbon atoms arranged in the shape of hollow, spherical cages called fullerenes. The soccer-ball-shaped buckminsterfullerene, or buckyballs, is an archetypal member of the fullerene family.
The alkali metal rubidium (pictured as blue spheres, above) occupy the vacant holes in between the polygons — changing the distance between neighboring buckyballs. This resulted in the highest achievable temperature for the onset of superconductivity: around 35 K or -238.15 degrees Celsius. That’s still very cold, yes, but it’s an improvement.
The material, Physics World explains, has a rich combination of insulating, magnetic, metallic, and superconducting phases. This includes the previously unknown intermediate phase, the Jahn-Teller metal state.