Scientists Image Wigner Crystal, a Solid Made of Electrons, After 90-Year Search
For the first time, scientists have created and photographed a Wigner crystal—a material made entirely of electrons—nearly 90 years after it was first theorized. The research, led by physicist Feng Wang at the University of California, Berkeley, was published last week in the journal Nature.
The team arranged electrons into a honeycomb-like lattice by sandwiching them in an electric field between two atom-thin layers of tungsten compounds. They achieved this by exploiting the tiniest differences in the atomic structures of the two layers, a feat that had eluded even the most accomplished physics labs until now.
Other researchers have previously claimed to create Wigner crystals, and Nature News noted they had some convincing evidence. But no one had presented imaged evidence of the crystal before. "If you say you have an electron crystal, show me the crystal," Wang told Nature News.
Because no camera could image the crystal directly, the scientists used a scanning tunneling microscope (STM). The instrument uses a probe to detect the exact location of the gridlocked electrons by observing how they respond to a tiny jolt of electricity.
Carmen Rubio, a physicist at Columbia University who was not involved in the experiment, told Nature News that performing STM on this system was a great advancement.
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