Princeton University researchers were able to examine an iron wire just one atom thick, utilizing a scanning-tunneling microscope. On the thread, they spotted a location on the ultra-thin thread, where the probability of finding the elusive particle was high, confirming an 80-year-old theory.
Ettore Majorana proposed the idea that these strange particles could exist in a theory proposed in the 1930's. The theoretical particle was named after the physicist, but was not observed in nature until now.
Fermions are a class of subatomic particles that are one group of the building blocks of matter.
Investigators utilized an ultrapure lead crystal, which naturally develops thin surface ridges, as a mold for the wire. Iron atoms placed inside one of the ridges formed into a thin wire, just one atom wide and three atoms thick. This wire, along with its attendant lead cast, were placed under a microscope, standing nearly two stories tall, floating to avoid vibrations. The metal piece were then cooled to 457 degrees Fahrenheit, just above absolute zero. The microscope detected an electrically-neutral signal at the end of the nanowire, a distinctive sign of Majorana fermions.
"This is the most direct way of looking for the Majorana fermion since it is expected to emerge at the edge of certain materials. If you want to find this particle within a material you have to use such a microscope, which allows you to see where it actually is," Ali Yazdani, professor of physics at Princeton University and leader of the research team, said.
Matter and anti-matter usually annihilate each other when they meet, releasing vast amounts of radiation in the process. Unusually, in Majorana fermions, this dichotomy results in a highly-stable particle. This could allow the unusual particles to be utilized in future technology. This research could lead to new computers based on the laws of quantum mechanics, which would operate at much faster speeds than current technology.
A video detailing the new discovery is available on the Princeton University Vimeo channel.
The simple iron and lead construction of the detector could allow other researchers to quickly and easily recreate the results of the experiment, provided they have access to a suitable scanning-tunneling microscope.
Discovery of the Majorana fermion was detailed in the journal Science.