Scientists have determined the existence of a new kind of matter called excitonium – first proposed nearly 50 years ago. Researchers from the University of California Berkeley and the University of Illinois at Urbana-Champaign in the US have been studying an unadulterated crystal of dichalcogenide titanium dieseline metal (1T-TiSe2).
Excitonium is a condensate – it exhibits macroscopic nature, like a superconductor. It is made of excitons, particles formed in a strange mechanical quantum pair, namely of an electron escaping from a hole.
Research shows that when an electron, which exists in semiconductor electronics, it is excited and jumps over the energy gap to a “molecular value hole”.
That hole seemingly functions like it were a massive particle with a positive charge, and it attracts the escaped electron.
When the electron leaves with its negative charge, paired with the hole, the two poles form a composite particle, an exciton unit. In fact, the properties of the particles around this hole are due to the gathering behavior of the surrounding electron particles.
Abbamonte and his team overcame a new challenge by using a new technique they developed called the emission electron energy loss spectrum (M-EELS). With this new technology, the team was able to measure the collective stimulation of low energy bosonic particles, electrons with holes connected, regardless of their dynamics.
Peter Abbamonte, a professor at the University of Illinois, said: “Ever since the term ‘excitonium’ was coined in the 1960s by Harvard theoretical physicist Bert Halperin, physicists have been trying to prove existence at the same time. The theorists debated whether it was the insulator, the perfect conductor or the superfluid. ”
“Since the 1970s, many experimentalists have published evidence for the existence of excitonium, but their findings are not definitive and can be explained by transforming the stage of pine structure often”, he said.
The researchers say these findings, published in the journal Science, promise to unlock more mysteries about quantum mechanics.
It can also shed light on the transition of metal insulators in ice solids, in which the exciton condensation is believed to be involved.