In a rigorous scientific venture, a team of researchers from the Delft University of Technology in the Netherlands, and the country’s Organisation for Applied Scientific Research have looked into signs of a unique phenomenon – ferromagnetism, first predicted by Japanese physicist Yosuke Nagaoka in 1966.
According to the paper published in Nature, ferromagnetism makes itself obvious in such everyday realities as universally popular refrigerator magnets –all electrons in them are characterised by a feature called “spin” that causes them to operate like tiny magnets on their own.
To visually demonstrate the unrivalled phenomenon, the scientists built a 2D, two-by-two lattice made up of quantum dots - semiconductor particles that may potentially be used to design the next generation of quantum computers and other devices capable of conducting record-breaking complicated calculations.
When the system was cooled down to absolute zero (-273.15°C or -459.67°F), three electrons were trapped inside it, leaving one “puzzle block” empty. Still, the lattice overall behaved like a magnet, as Nagaoka originally suggested.
In the scientist’s version of the magnetic puzzle, all the electrons are aligned in the same way, thereby creating a magnetic field, and most importantly, the puzzle blocks are shuffled and reshuffled yet the magnetism of the system as a whole remains intact.
"We used a very sensitive electric sensor which could decipher the spin orientation of the electrons and convert it into an electrical signal that we could measure in the lab", says quantum physicist Uditendu Mukhopadhyay, from Delft University of Technology.
The sensor demonstrated that the super-small, super-delicate quantum dot system did indeed align the electron spins as anticipated, largely preferring the lowest energy level.
The range of projected applications of the novel feature is vast indeed:
"Such systems permit the study of problems that are too complex to solve with today's most advanced supercomputer, for example complex chemical processes", says quantum physicist Lieven Vandersypen, from the Delft University of Technology in the Netherlands, adding that the research may also facilitate the build-up of simulators of the future.