In 1937, Italian theoretical physicist Ettore Majorana proposed the existence of a particle that is both matter and antimatter. Now, physicists from the Princeton University have finally found this elusive particle.
Matter and antimatter have equal mass but are oppositely charged. When matter, which is abundant in the universe, and the much rarer antimatter come in contact, they annihilate each other. Majorana predicted that some particles could be their own antimatter partners; the idea goes against the standard relationship of matter and antimatter in that they do not annihilate when they meet.
Many forms of antimatter have already been seen since the days of the physicist but the Majorana particle, which is matter and antimatter at the same time has been very elusive. A group of researchers, however, has finally found a particle that behaves like matter and antimatter.
Ali Yazdani from the Joseph Henry Laboratories and department of physics at the Princeton University and colleagues captured the image of a particle that they believed to be the elusive Majorana fermion by constructing a magnetic iron wire on a superconductor surface made of lead and using a highly sophisticated microscope at an ultralow-vibration laboratory.
"Using high-resolution spectroscopic imaging techniques, we show that the onset of superconductivity, which gaps the electronic density of states in the bulk of the Fe chains, is accompanied by the appearance of zero energy end states," the researchers wrote.
The study, published in the journal Science on Oct. 2, showed that the superconductivity in the iron wire matched the parameters required for the Majorana to be produced. "This spatially resolved signature provides strong evidence, corroborated by other observations, for the formation of a topological phase and edge-bound Majorana fermions in our atomic chains."
The researchers discovered that the system they use is highly likely to have Majorana fermion provided there exist the features of superconductivity and magnetism. It is also previously thought that generating Majoranas involve using special forms of magnetism, but the researchers said that the particle could also be present in common forms of magnetism, such as the one in iron.
Study researcher and physics professor at Princeton University B. Andrei Bernevig said that as long as there is a strong magnetic material where the electrons are magnetically polarized or the electrons sense very strong magnetic fields, the possibility of the Majoranas appearing increases dramatically.
"Once you have that, all you need are some relativistic effects that are easy to induce at the surface of a heavy element like lead, and the Majoranas will appear," Bernevig said.