Scientists have spent 50 years trying to find the evidence of a new form of matter called excitonium. The scientists came up with the name during the 1960s, which was initially suggested by Bert Halperin, a Harvard theoretical physicist , who is now 76 years old. As Newsweek reports, the physicist behind the discovery of the matter excitonium, Peter Abbamonte, saw Halperin at a party recently, describing him as seeming excited about the excitonium discovery.
“It’s as close to be ‘proved’ as you’re ever going to get in science,” Peter Abbamonte, a physics professor at the University of Illionis at Urbana-Champaign, told Newsweek. “You can never really ‘prove’ anything, but, well, people find it convincing,” he added.
Matter excitonium is a condensate, which means that it has been detected in a solid state. The new form of matter has been made up of particles called excitons, which is exactly the same as aluminum being created of small aluminum particles. However, it’s worth mentioning that the exciton particles aren’t made up through as easy a process as other particles.
Let’s compare the new matter to an element such as hydrogen. The hydrogen particles consist of an electron and a proton. On the other hand, excitons are a sort of a boson which is formed in a semiconductor. An electron which is located at the edge of a semiconductor’s valence gets excited and once it is excited, it can escape the band gap to the conducted band, which is empty. An escaped electron leaves a “hole” in the valence band, which is charged with positive charge. The two positive charged holes attract each other and orbit each other in a way to form the exciton.
Even though scientists in the past suggested theories that would suggest this particle existed, they never had any evidence. Abbamonte and his colleagues managed to invent a new technique called the electron-scattering technique to detect exciton particles and excitonium itself. They started on a clean surface of the material in a vacuum, which, as you may know, doesn’t have air in it. They scattered the electrons from the surface to make waves. The waves were spreading in a way that allowed the scientists to detect the new form of matter.
They started working on the scattering technique roughly seven years ago, although it couldn’t detect excitonium because of the way it was designed. In 2015 they used “total serendipity” according to Abbamonte to study the high-temperature superconductor, which allowed them to potentially prove that the matter excitonium was real. However, many things about this new form of matter are unknown, as scientists don’t know what its properties are. According to Abbamonte, speculations suggest that the element could be an insulator and that it can’t carry energy or momentum, while other people believe it is a superfluid, and that it can carry either energy and momentum with no dissipation, which is exactly the opposite of the initial speculations.
“The most important thing is that it exists,” Abbamonte told Newsweek. “it’s one of those things that just ought to be there, you know? And it didn’t make sense that it wasn’t.”
