Phys.org  July 1, 2021 An international team of researchers (Switzerland, USA – Harvard University, Germany, Japan) has succeeded in observing Wigner crystals which consist of only electrons predicted almost ninety years ago. The team used optical spectroscopy to demonstrate that electrons in a monolayer semiconductor with density lower than 3 × 1011 per centimetre squared. The combination of a high electron effective mass and reduced dielectric screening enabled them to observe electronic charge order even in the absence of a moiré potential or an external magnetic field. The findings demonstrate that charge-tunable transition metal dichalcogenide monolayers enable the investigation of […]