Phys.org November 17, 2024
Semiconductor Moiré superlattices provide a versatile platform to engineer quantum solids composed of artificial atoms on moiré sites. Previous studies have mostly focused on the simplest correlated quantum solid—the Fermi-Hubbard model—in which intra-atom interactions are simplified to a single onsite repulsion energy. An international team of researchers (USA – UC Berkeley, Lawrence Berkeley National Laboratory, MIT, University of Arizona, Japan) experimentally observed Wigner molecular crystals emerging from multielectron artificial atoms in twisted bilayer tungsten disulfide moiré superlattices. Using scanning tunneling microscopy, they demonstrated that Wigner molecules appeared in multielectron artificial atoms when Coulomb interactions dominated. The array of Wigner molecules observed in a moiré superlattice comprised a crystalline phase of electrons, the Wigner molecular crystal was shown to be highly tunable through mechanical strain, moiré period, and carrier charge type… read more. TECHNICAL ARTICLE
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From top left: Scanning tunneling microscope images of electrons evolving into a single Wigner molecule (bottom right). Credit: Berkeley La.