Scientists have discovered a new state of matter, called 'Jahn-Teller metals'

An international team of scientists has announced the discovery of a new state of matter in a material that appears to be an insulator, superconductor, metal and magnet all rolled into one, saying that it could lead to the development of more effective high-temperature superconductors.
Why is this so exciting? Well, if these properties are confirmed, this new state of matter will allow scientists to better understand why some materials have the potential to achieve superconductivity at a relativity high critical temperature (Tc) - "high" as in −135 °C as opposed to −243.2 °C. Because superconductivity allows a material to conduct electricity without resistance, which means no heat, sound, or any other form of energy release, achieving this would revolutionise how we use and produce energy, but it’s only feasible if we can achieve it at so-called high temperatures.
As Michael Byrne explains at Motherboard, when we talk about states of matter, it’s not just solids, liquids, gases, and maybe plasmas that we have to think about. We also have to consider the more obscure states that don’t occur in nature, but are rather created in the lab - Bose–Einstein condensate, degenerate matter, supersolids and superfluids, and quark-gluon plasma, for example. 
By introducing rubidium into carbon-60 molecules - more commonly known as 'buckyballs' - a team led by chemist Kosmas Prassides from Tokohu University in Japan was able to change the distance between them, which forced them into a new, crystalline structure. When put through an array of tests, this structure displayed a combination of insulating, superconducting, metallic, and magnetic phases, including a brand new one, which the researchers have named 'Jahn-Teller metals'. 

more info: