For the first time, the possibility of creating a crystal, fully consisting of electrons, was predicted by the American physicist Eugene Wigner in 1934. In the future, such a crystal was named in his honor. However, in order to realize the theory in life, scientists took 90 years.
The first of the Vigner crystal was the engineers of the Swiss Higher Technical School of Zurich (Eth Zurich), and more recently, their colleagues, physicists from the University of California, using a scanning tunnel microscope, took a picture of the graphene sheet, inside of which the desired crystals were formed.
To get them, the team of scientists led by the physicist of Feng Van has developed a material consisting of two layers with a thickness of the tungsten (WS2) and tungsten dysolenid (WSE2). After that, the researchers using an electric field set up the density of electrons, freely moving along the border of the section between layers.
Electrons in ordinary materials move so rapidly that they are practically not affected by the forces of repulsing their opposite charges. Eugene Vigner at one time suggested that when the electrons in their behavior, it would be repulsive. Based on this, Van and his colleagues slowed the electrons in their material, cooling them to a temperature just above the absolute zero (-273 ° C).
The contrast formed between two layers helped the electrons to form Vigner crystals. Atoms in each of the layers are located on different distance from each other, as a result, such a compound is created by a peculiar cell “muaric pattern”, reminiscent of the imposition of two nets.
Source — Nature News